FRE-600: Fix code review blockers

- Consolidated duplicate UndoManagers to single instance
- Fixed connection promise to only resolve on 'connected' status
- Fixed WebSocketProvider import (WebsocketProvider)
- Added proper doc.destroy() cleanup
- Renamed isPresenceInitialized property to avoid conflict

Co-Authored-By: Paperclip <noreply@paperclip.ing>

node_modules/y-websocket/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2019 Kevin Jahns <kevin.jahns@protonmail.com>.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

node_modules/y-websocket/README.md

@@ -0,0 +1,146 @@
+
+# y-websocket :tophat:
+> WebSocket Provider for Yjs
+
+The Websocket Provider implements a classical client server model. Clients connect to a single endpoint over Websocket. The server distributes awareness information and document updates among clients.
+
+The Websocket Provider is a solid choice if you want a central source that handles authentication and authorization. Websockets also send header information and cookies, so you can use existing authentication mechanisms with this server.
+
+* Supports cross-tab communication. When you open the same document in the same browser, changes on the document are exchanged via cross-tab communication ([Broadcast Channel](https://developer.mozilla.org/en-US/docs/Web/API/Broadcast_Channel_API) and [localStorage](https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage) as fallback).
+* Supports exchange of awareness information (e.g. cursors).
+
+## Quick Start
+
+### Install dependencies
+
+```sh
+npm i y-websocket
+```
+
+### Start a y-websocket server
+
+This repository implements a basic server that you can adopt to your specific use-case. [(source code)](./bin/)
+
+Start a y-websocket server:
+
+```sh
+HOST=localhost PORT=1234 npx y-websocket
+```
+
+### Client Code:
+
+```js
+import * as Y from 'yjs'
+import { WebsocketProvider } from 'y-websocket'
+
+const doc = new Y.Doc()
+const wsProvider = new WebsocketProvider('ws://localhost:1234', 'my-roomname', doc)
+
+wsProvider.on('status', event => {
+  console.log(event.status) // logs "connected" or "disconnected"
+})
+```
+
+#### Client Code in Node.js
+
+The WebSocket provider requires a [`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket) object to create connection to a server. You can polyfill WebSocket support in Node.js using the [`ws` package](https://www.npmjs.com/package/ws).
+
+```js
+const wsProvider = new WebsocketProvider('ws://localhost:1234', 'my-roomname', doc, { WebSocketPolyfill: require('ws') })
+```
+
+## API
+
+```js
+import { WebsocketProvider } from 'y-websocket'
+```
+
+<dl>
+  <b><code>wsProvider = new WebsocketProvider(serverUrl: string, room: string, ydoc: Y.Doc [, wsOpts: WsOpts])</code></b>
+  <dd>Create a new websocket-provider instance. As long as this provider, or the connected ydoc, is not destroyed, the changes will be synced to other clients via the connected server. Optionally, you may specify a configuration object. The following default values of wsOpts can be overwritten. </dd>
+</dl>
+
+```js
+wsOpts = {
+  // Set this to `false` if you want to connect manually using wsProvider.connect()
+  connect: true,
+  // Specify a query-string that will be url-encoded and attached to the `serverUrl`
+  // I.e. params = { auth: "bearer" } will be transformed to "?auth=bearer"
+  params: {}, // Object<string,string>
+  // You may polyill the Websocket object (https://developer.mozilla.org/en-US/docs/Web/API/WebSocket).
+  // E.g. In nodejs, you could specify WebsocketPolyfill = require('ws')
+  WebsocketPolyfill: Websocket,
+  // Specify an existing Awareness instance - see https://github.com/yjs/y-protocols
+  awareness: new awarenessProtocol.Awareness(ydoc),
+  // Specify the maximum amount to wait between reconnects (we use exponential backoff).
+  maxBackoffTime: 2500
+}
+```
+
+<dl>
+  <b><code>wsProvider.wsconnected: boolean</code></b>
+  <dd>True if this instance is currently connected to the server.</dd>
+  <b><code>wsProvider.wsconnecting: boolean</code></b>
+  <dd>True if this instance is currently connecting to the server.</dd>
+  <b><code>wsProvider.shouldConnect: boolean</code></b>
+  <dd>If false, the client will not try to reconnect.</dd>
+  <b><code>wsProvider.bcconnected: boolean</code></b>
+  <dd>True if this instance is currently communicating to other browser-windows via BroadcastChannel.</dd>
+  <b><code>wsProvider.synced: boolean</code></b>
+  <dd>True if this instance is currently connected and synced with the server.</dd>
+  <b><code>wsProvider.disconnect()</code></b>
+  <dd>Disconnect from the server and don't try to reconnect.</dd>
+  <b><code>wsProvider.connect()</code></b>
+  <dd>Establish a websocket connection to the websocket-server. Call this if you recently disconnected or if you set wsOpts.connect = false.</dd>
+  <b><code>wsProvider.destroy()</code></b>
+  <dd>Destroy this wsProvider instance. Disconnects from the server and removes all event handlers.</dd>
+  <b><code>wsProvider.on('sync', function(isSynced: boolean))</code></b>
+  <dd>Add an event listener for the sync event that is fired when the client received content from the server.</dd>
+  <b><code>wsProvider.on('status', function({ status: 'disconnected' | 'connecting' | 'connected' }))</code></b>
+  <dd>Receive updates about the current connection status.</dd>
+  <b><code>wsProvider.on('connection-close', function(WSClosedEvent))</code></b>
+  <dd>Fires when the underlying websocket connection is closed. It forwards the websocket event to this event handler.</dd>
+  <b><code>wsProvider.on('connection-error', function(WSErrorEvent))</code></b>
+  <dd>Fires when the underlying websocket connection closes with an error. It forwards the websocket event to this event handler.</dd>
+</dl>
+
+## Websocket Server
+
+Start a y-websocket server:
+
+```sh
+HOST=localhost PORT=1234 npx y-websocket
+```
+
+Since npm symlinks the `y-websocket` executable from your local `./node_modules/.bin` folder, you can simply run npx. The `PORT` environment variable already defaults to 1234, and `HOST` defaults to `localhost`.
+
+### Websocket Server with Persistence
+
+Persist document updates in a LevelDB database.
+
+See [LevelDB Persistence](https://github.com/yjs/y-leveldb) for more info.
+
+```sh
+HOST=localhost PORT=1234 YPERSISTENCE=./dbDir node ./node_modules/y-websocket/bin/server.js
+```
+
+### Websocket Server with HTTP callback
+
+Send a debounced callback to an HTTP server (`POST`) on document update. Note that this implementation doesn't implement a retry logic in case the `CALLBACK_URL` does not work.
+
+Can take the following ENV variables:
+
+* `CALLBACK_URL` : Callback server URL
+* `CALLBACK_DEBOUNCE_WAIT` : Debounce time between callbacks (in ms). Defaults to 2000 ms
+* `CALLBACK_DEBOUNCE_MAXWAIT` : Maximum time to wait before callback. Defaults to 10 seconds
+* `CALLBACK_TIMEOUT` : Timeout for the HTTP call. Defaults to 5 seconds
+* `CALLBACK_OBJECTS` : JSON of shared objects to get data (`'{"SHARED_OBJECT_NAME":"SHARED_OBJECT_TYPE}'`)
+
+```sh
+CALLBACK_URL=http://localhost:3000/ CALLBACK_OBJECTS='{"prosemirror":"XmlFragment"}' npm start
+```
+This sends a debounced callback to `localhost:3000` 2 seconds after receiving an update (default `DEBOUNCE_WAIT`) with the data of an XmlFragment named `"prosemirror"` in the body.
+
+## License
+
+[The MIT License](./LICENSE) © Kevin Jahns

node_modules/y-websocket/bin/callback.js

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+const http = require('http')
+
+const CALLBACK_URL = process.env.CALLBACK_URL ? new URL(process.env.CALLBACK_URL) : null
+const CALLBACK_TIMEOUT = process.env.CALLBACK_TIMEOUT || 5000
+const CALLBACK_OBJECTS = process.env.CALLBACK_OBJECTS ? JSON.parse(process.env.CALLBACK_OBJECTS) : {}
+
+exports.isCallbackSet = !!CALLBACK_URL
+
+/**
+ * @param {Uint8Array} update
+ * @param {any} origin
+ * @param {WSSharedDoc} doc
+ */
+exports.callbackHandler = (update, origin, doc) => {
+  const room = doc.name
+  const dataToSend = {
+    room,
+    data: {}
+  }
+  const sharedObjectList = Object.keys(CALLBACK_OBJECTS)
+  sharedObjectList.forEach(sharedObjectName => {
+    const sharedObjectType = CALLBACK_OBJECTS[sharedObjectName]
+    dataToSend.data[sharedObjectName] = {
+      type: sharedObjectType,
+      content: getContent(sharedObjectName, sharedObjectType, doc).toJSON()
+    }
+  })
+  callbackRequest(CALLBACK_URL, CALLBACK_TIMEOUT, dataToSend)
+}
+
+/**
+ * @param {URL} url
+ * @param {number} timeout
+ * @param {Object} data
+ */
+const callbackRequest = (url, timeout, data) => {
+  data = JSON.stringify(data)
+  const options = {
+    hostname: url.hostname,
+    port: url.port,
+    path: url.pathname,
+    timeout,
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/json',
+      'Content-Length': data.length
+    }
+  }
+  const req = http.request(options)
+  req.on('timeout', () => {
+    console.warn('Callback request timed out.')
+    req.abort()
+  })
+  req.on('error', (e) => {
+    console.error('Callback request error.', e)
+    req.abort()
+  })
+  req.write(data)
+  req.end()
+}
+
+/**
+ * @param {string} objName
+ * @param {string} objType
+ * @param {WSSharedDoc} doc
+ */
+const getContent = (objName, objType, doc) => {
+  switch (objType) {
+    case 'Array': return doc.getArray(objName)
+    case 'Map': return doc.getMap(objName)
+    case 'Text': return doc.getText(objName)
+    case 'XmlFragment': return doc.getXmlFragment(objName)
+    case 'XmlElement': return doc.getXmlElement(objName)
+    default : return {}
+  }
+}

node_modules/y-websocket/bin/server.js

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+#!/usr/bin/env node
+
+/**
+ * @type {any}
+ */
+const WebSocket = require('ws')
+const http = require('http')
+const wss = new WebSocket.Server({ noServer: true })
+const setupWSConnection = require('./utils.js').setupWSConnection
+
+const host = process.env.HOST || 'localhost'
+const port = process.env.PORT || 1234
+
+const server = http.createServer((request, response) => {
+  response.writeHead(200, { 'Content-Type': 'text/plain' })
+  response.end('okay')
+})
+
+wss.on('connection', setupWSConnection)
+
+server.on('upgrade', (request, socket, head) => {
+  // You may check auth of request here..
+  // See https://github.com/websockets/ws#client-authentication
+  /**
+   * @param {any} ws
+   */
+  const handleAuth = ws => {
+    wss.emit('connection', ws, request)
+  }
+  wss.handleUpgrade(request, socket, head, handleAuth)
+})
+
+server.listen(port, host, () => {
+  console.log(`running at '${host}' on port ${port}`)
+})

node_modules/y-websocket/bin/utils.js

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+const Y = require('yjs')
+const syncProtocol = require('y-protocols/dist/sync.cjs')
+const awarenessProtocol = require('y-protocols/dist/awareness.cjs')
+
+const encoding = require('lib0/dist/encoding.cjs')
+const decoding = require('lib0/dist/decoding.cjs')
+const map = require('lib0/dist/map.cjs')
+
+const debounce = require('lodash.debounce')
+
+const callbackHandler = require('./callback.js').callbackHandler
+const isCallbackSet = require('./callback.js').isCallbackSet
+
+const CALLBACK_DEBOUNCE_WAIT = parseInt(process.env.CALLBACK_DEBOUNCE_WAIT) || 2000
+const CALLBACK_DEBOUNCE_MAXWAIT = parseInt(process.env.CALLBACK_DEBOUNCE_MAXWAIT) || 10000
+
+const wsReadyStateConnecting = 0
+const wsReadyStateOpen = 1
+const wsReadyStateClosing = 2 // eslint-disable-line
+const wsReadyStateClosed = 3 // eslint-disable-line
+
+// disable gc when using snapshots!
+const gcEnabled = process.env.GC !== 'false' && process.env.GC !== '0'
+const persistenceDir = process.env.YPERSISTENCE
+/**
+ * @type {{bindState: function(string,WSSharedDoc):void, writeState:function(string,WSSharedDoc):Promise<any>, provider: any}|null}
+ */
+let persistence = null
+if (typeof persistenceDir === 'string') {
+  console.info('Persisting documents to "' + persistenceDir + '"')
+  // @ts-ignore
+  const LeveldbPersistence = require('y-leveldb').LeveldbPersistence
+  const ldb = new LeveldbPersistence(persistenceDir)
+  persistence = {
+    provider: ldb,
+    bindState: async (docName, ydoc) => {
+      const persistedYdoc = await ldb.getYDoc(docName)
+      const newUpdates = Y.encodeStateAsUpdate(ydoc)
+      ldb.storeUpdate(docName, newUpdates)
+      Y.applyUpdate(ydoc, Y.encodeStateAsUpdate(persistedYdoc))
+      ydoc.on('update', update => {
+        ldb.storeUpdate(docName, update)
+      })
+    },
+    writeState: async (docName, ydoc) => {}
+  }
+}
+
+/**
+ * @param {{bindState: function(string,WSSharedDoc):void,
+ * writeState:function(string,WSSharedDoc):Promise<any>,provider:any}|null} persistence_
+ */
+exports.setPersistence = persistence_ => {
+  persistence = persistence_
+}
+
+/**
+ * @return {null|{bindState: function(string,WSSharedDoc):void,
+  * writeState:function(string,WSSharedDoc):Promise<any>}|null} used persistence layer
+  */
+exports.getPersistence = () => persistence
+
+/**
+ * @type {Map<string,WSSharedDoc>}
+ */
+const docs = new Map()
+// exporting docs so that others can use it
+exports.docs = docs
+
+const messageSync = 0
+const messageAwareness = 1
+// const messageAuth = 2
+
+/**
+ * @param {Uint8Array} update
+ * @param {any} origin
+ * @param {WSSharedDoc} doc
+ */
+const updateHandler = (update, origin, doc) => {
+  const encoder = encoding.createEncoder()
+  encoding.writeVarUint(encoder, messageSync)
+  syncProtocol.writeUpdate(encoder, update)
+  const message = encoding.toUint8Array(encoder)
+  doc.conns.forEach((_, conn) => send(doc, conn, message))
+}
+
+class WSSharedDoc extends Y.Doc {
+  /**
+   * @param {string} name
+   */
+  constructor (name) {
+    super({ gc: gcEnabled })
+    this.name = name
+    /**
+     * Maps from conn to set of controlled user ids. Delete all user ids from awareness when this conn is closed
+     * @type {Map<Object, Set<number>>}
+     */
+    this.conns = new Map()
+    /**
+     * @type {awarenessProtocol.Awareness}
+     */
+    this.awareness = new awarenessProtocol.Awareness(this)
+    this.awareness.setLocalState(null)
+    /**
+     * @param {{ added: Array<number>, updated: Array<number>, removed: Array<number> }} changes
+     * @param {Object | null} conn Origin is the connection that made the change
+     */
+    const awarenessChangeHandler = ({ added, updated, removed }, conn) => {
+      const changedClients = added.concat(updated, removed)
+      if (conn !== null) {
+        const connControlledIDs = /** @type {Set<number>} */ (this.conns.get(conn))
+        if (connControlledIDs !== undefined) {
+          added.forEach(clientID => { connControlledIDs.add(clientID) })
+          removed.forEach(clientID => { connControlledIDs.delete(clientID) })
+        }
+      }
+      // broadcast awareness update
+      const encoder = encoding.createEncoder()
+      encoding.writeVarUint(encoder, messageAwareness)
+      encoding.writeVarUint8Array(encoder, awarenessProtocol.encodeAwarenessUpdate(this.awareness, changedClients))
+      const buff = encoding.toUint8Array(encoder)
+      this.conns.forEach((_, c) => {
+        send(this, c, buff)
+      })
+    }
+    this.awareness.on('update', awarenessChangeHandler)
+    this.on('update', updateHandler)
+    if (isCallbackSet) {
+      this.on('update', debounce(
+        callbackHandler,
+        CALLBACK_DEBOUNCE_WAIT,
+        { maxWait: CALLBACK_DEBOUNCE_MAXWAIT }
+      ))
+    }
+  }
+}
+
+/**
+ * Gets a Y.Doc by name, whether in memory or on disk
+ *
+ * @param {string} docname - the name of the Y.Doc to find or create
+ * @param {boolean} gc - whether to allow gc on the doc (applies only when created)
+ * @return {WSSharedDoc}
+ */
+const getYDoc = (docname, gc = true) => map.setIfUndefined(docs, docname, () => {
+  const doc = new WSSharedDoc(docname)
+  doc.gc = gc
+  if (persistence !== null) {
+    persistence.bindState(docname, doc)
+  }
+  docs.set(docname, doc)
+  return doc
+})
+
+exports.getYDoc = getYDoc
+
+/**
+ * @param {any} conn
+ * @param {WSSharedDoc} doc
+ * @param {Uint8Array} message
+ */
+const messageListener = (conn, doc, message) => {
+  try {
+    const encoder = encoding.createEncoder()
+    const decoder = decoding.createDecoder(message)
+    const messageType = decoding.readVarUint(decoder)
+    switch (messageType) {
+      case messageSync:
+        encoding.writeVarUint(encoder, messageSync)
+        syncProtocol.readSyncMessage(decoder, encoder, doc, conn)
+
+        // If the `encoder` only contains the type of reply message and no
+        // message, there is no need to send the message. When `encoder` only
+        // contains the type of reply, its length is 1.
+        if (encoding.length(encoder) > 1) {
+          send(doc, conn, encoding.toUint8Array(encoder))
+        }
+        break
+      case messageAwareness: {
+        awarenessProtocol.applyAwarenessUpdate(doc.awareness, decoding.readVarUint8Array(decoder), conn)
+        break
+      }
+    }
+  } catch (err) {
+    console.error(err)
+    doc.emit('error', [err])
+  }
+}
+
+/**
+ * @param {WSSharedDoc} doc
+ * @param {any} conn
+ */
+const closeConn = (doc, conn) => {
+  if (doc.conns.has(conn)) {
+    /**
+     * @type {Set<number>}
+     */
+    // @ts-ignore
+    const controlledIds = doc.conns.get(conn)
+    doc.conns.delete(conn)
+    awarenessProtocol.removeAwarenessStates(doc.awareness, Array.from(controlledIds), null)
+    if (doc.conns.size === 0 && persistence !== null) {
+      // if persisted, we store state and destroy ydocument
+      persistence.writeState(doc.name, doc).then(() => {
+        doc.destroy()
+      })
+      docs.delete(doc.name)
+    }
+  }
+  conn.close()
+}
+
+/**
+ * @param {WSSharedDoc} doc
+ * @param {any} conn
+ * @param {Uint8Array} m
+ */
+const send = (doc, conn, m) => {
+  if (conn.readyState !== wsReadyStateConnecting && conn.readyState !== wsReadyStateOpen) {
+    closeConn(doc, conn)
+  }
+  try {
+    conn.send(m, /** @param {any} err */ err => { err != null && closeConn(doc, conn) })
+  } catch (e) {
+    closeConn(doc, conn)
+  }
+}
+
+const pingTimeout = 30000
+
+/**
+ * @param {any} conn
+ * @param {any} req
+ * @param {any} opts
+ */
+exports.setupWSConnection = (conn, req, { docName = req.url.slice(1).split('?')[0], gc = true } = {}) => {
+  conn.binaryType = 'arraybuffer'
+  // get doc, initialize if it does not exist yet
+  const doc = getYDoc(docName, gc)
+  doc.conns.set(conn, new Set())
+  // listen and reply to events
+  conn.on('message', /** @param {ArrayBuffer} message */ message => messageListener(conn, doc, new Uint8Array(message)))
+
+  // Check if connection is still alive
+  let pongReceived = true
+  const pingInterval = setInterval(() => {
+    if (!pongReceived) {
+      if (doc.conns.has(conn)) {
+        closeConn(doc, conn)
+      }
+      clearInterval(pingInterval)
+    } else if (doc.conns.has(conn)) {
+      pongReceived = false
+      try {
+        conn.ping()
+      } catch (e) {
+        closeConn(doc, conn)
+        clearInterval(pingInterval)
+      }
+    }
+  }, pingTimeout)
+  conn.on('close', () => {
+    closeConn(doc, conn)
+    clearInterval(pingInterval)
+  })
+  conn.on('pong', () => {
+    pongReceived = true
+  })
+  // put the following in a variables in a block so the interval handlers don't keep in in
+  // scope
+  {
+    // send sync step 1
+    const encoder = encoding.createEncoder()
+    encoding.writeVarUint(encoder, messageSync)
+    syncProtocol.writeSyncStep1(encoder, doc)
+    send(doc, conn, encoding.toUint8Array(encoder))
+    const awarenessStates = doc.awareness.getStates()
+    if (awarenessStates.size > 0) {
+      const encoder = encoding.createEncoder()
+      encoding.writeVarUint(encoder, messageAwareness)
+      encoding.writeVarUint8Array(encoder, awarenessProtocol.encodeAwarenessUpdate(doc.awareness, Array.from(awarenessStates.keys())))
+      send(doc, conn, encoding.toUint8Array(encoder))
+    }
+  }
+}

node_modules/y-websocket/dist/src/y-websocket.d.ts

@@ -0,0 +1,120 @@
+export const messageSync: 0;
+export const messageQueryAwareness: 3;
+export const messageAwareness: 1;
+export const messageAuth: 2;
+/**
+ * Websocket Provider for Yjs. Creates a websocket connection to sync the shared document.
+ * The document name is attached to the provided url. I.e. the following example
+ * creates a websocket connection to http://localhost:1234/my-document-name
+ *
+ * @example
+ *   import * as Y from 'yjs'
+ *   import { WebsocketProvider } from 'y-websocket'
+ *   const doc = new Y.Doc()
+ *   const provider = new WebsocketProvider('http://localhost:1234', 'my-document-name', doc)
+ *
+ * @extends {Observable<string>}
+ */
+export class WebsocketProvider extends Observable<string> {
+    /**
+     * @param {string} serverUrl
+     * @param {string} roomname
+     * @param {Y.Doc} doc
+     * @param {object} opts
+     * @param {boolean} [opts.connect]
+     * @param {awarenessProtocol.Awareness} [opts.awareness]
+     * @param {Object<string,string>} [opts.params]
+     * @param {typeof WebSocket} [opts.WebSocketPolyfill] Optionall provide a WebSocket polyfill
+     * @param {number} [opts.resyncInterval] Request server state every `resyncInterval` milliseconds
+     * @param {number} [opts.maxBackoffTime] Maximum amount of time to wait before trying to reconnect (we try to reconnect using exponential backoff)
+     * @param {boolean} [opts.disableBc] Disable cross-tab BroadcastChannel communication
+     */
+    constructor(serverUrl: string, roomname: string, doc: Y.Doc, { connect, awareness, params, WebSocketPolyfill, resyncInterval, maxBackoffTime, disableBc }?: {
+        connect?: boolean | undefined;
+        awareness?: awarenessProtocol.Awareness | undefined;
+        params?: {
+            [x: string]: string;
+        } | undefined;
+        WebSocketPolyfill?: {
+            new (url: string | URL, protocols?: string | string[] | undefined): WebSocket;
+            prototype: WebSocket;
+            readonly CLOSED: number;
+            readonly CLOSING: number;
+            readonly CONNECTING: number;
+            readonly OPEN: number;
+        } | undefined;
+        resyncInterval?: number | undefined;
+        maxBackoffTime?: number | undefined;
+        disableBc?: boolean | undefined;
+    });
+    maxBackoffTime: number;
+    bcChannel: string;
+    url: string;
+    roomname: string;
+    doc: Y.Doc;
+    _WS: {
+        new (url: string | URL, protocols?: string | string[] | undefined): WebSocket;
+        prototype: WebSocket;
+        readonly CLOSED: number;
+        readonly CLOSING: number;
+        readonly CONNECTING: number;
+        readonly OPEN: number;
+    };
+    awareness: awarenessProtocol.Awareness;
+    wsconnected: boolean;
+    wsconnecting: boolean;
+    bcconnected: boolean;
+    disableBc: boolean;
+    wsUnsuccessfulReconnects: number;
+    messageHandlers: ((arg0: encoding.Encoder, arg1: decoding.Decoder, arg2: WebsocketProvider, arg3: boolean, arg4: number) => void)[];
+    /**
+     * @type {boolean}
+     */
+    _synced: boolean;
+    /**
+     * @type {WebSocket?}
+     */
+    ws: WebSocket | null;
+    wsLastMessageReceived: number;
+    /**
+     * Whether to connect to other peers or not
+     * @type {boolean}
+     */
+    shouldConnect: boolean;
+    /**
+     * @type {number}
+     */
+    _resyncInterval: number;
+    /**
+     * @param {ArrayBuffer} data
+     * @param {any} origin
+     */
+    _bcSubscriber: (data: ArrayBuffer, origin: any) => void;
+    /**
+     * Listens to Yjs updates and sends them to remote peers (ws and broadcastchannel)
+     * @param {Uint8Array} update
+     * @param {any} origin
+     */
+    _updateHandler: (update: Uint8Array, origin: any) => void;
+    /**
+     * @param {any} changed
+     * @param {any} _origin
+     */
+    _awarenessUpdateHandler: ({ added, updated, removed }: any, _origin: any) => void;
+    _exitHandler: () => void;
+    _checkInterval: any;
+    set synced(arg: boolean);
+    /**
+     * @type {boolean}
+     */
+    get synced(): boolean;
+    connectBc(): void;
+    disconnectBc(): void;
+    disconnect(): void;
+    connect(): void;
+}
+import { Observable } from "lib0/observable";
+import * as Y from "yjs";
+import * as awarenessProtocol from "y-protocols/awareness";
+import * as encoding from "lib0/encoding";
+import * as decoding from "lib0/decoding";

node_modules/y-websocket/dist/y-websocket.cjs

@@ -0,0 +1,520 @@
+'use strict';
+
+require('yjs');
+var bc = require('lib0/dist/broadcastchannel.cjs');
+var time = require('lib0/dist/time.cjs');
+var encoding = require('lib0/dist/encoding.cjs');
+var decoding = require('lib0/dist/decoding.cjs');
+var syncProtocol = require('y-protocols/dist/sync.cjs');
+var authProtocol = require('y-protocols/dist/auth.cjs');
+var awarenessProtocol = require('y-protocols/dist/awareness.cjs');
+var observable = require('lib0/dist/observable.cjs');
+var math = require('lib0/dist/math.cjs');
+var url = require('lib0/dist/url.cjs');
+var env = require('lib0/dist/environment.cjs');
+
+function _interopNamespaceDefault(e) {
+  var n = Object.create(null);
+  if (e) {
+    Object.keys(e).forEach(function (k) {
+      if (k !== 'default') {
+        var d = Object.getOwnPropertyDescriptor(e, k);
+        Object.defineProperty(n, k, d.get ? d : {
+          enumerable: true,
+          get: function () { return e[k]; }
+        });
+      }
+    });
+  }
+  n.default = e;
+  return Object.freeze(n);
+}
+
+var bc__namespace = /*#__PURE__*/_interopNamespaceDefault(bc);
+var time__namespace = /*#__PURE__*/_interopNamespaceDefault(time);
+var encoding__namespace = /*#__PURE__*/_interopNamespaceDefault(encoding);
+var decoding__namespace = /*#__PURE__*/_interopNamespaceDefault(decoding);
+var syncProtocol__namespace = /*#__PURE__*/_interopNamespaceDefault(syncProtocol);
+var authProtocol__namespace = /*#__PURE__*/_interopNamespaceDefault(authProtocol);
+var awarenessProtocol__namespace = /*#__PURE__*/_interopNamespaceDefault(awarenessProtocol);
+var math__namespace = /*#__PURE__*/_interopNamespaceDefault(math);
+var url__namespace = /*#__PURE__*/_interopNamespaceDefault(url);
+var env__namespace = /*#__PURE__*/_interopNamespaceDefault(env);
+
+/**
+ * @module provider/websocket
+ */
+
+const messageSync = 0;
+const messageQueryAwareness = 3;
+const messageAwareness = 1;
+const messageAuth = 2;
+
+/**
+ *                       encoder,          decoder,          provider,          emitSynced, messageType
+ * @type {Array<function(encoding.Encoder, decoding.Decoder, WebsocketProvider, boolean,    number):void>}
+ */
+const messageHandlers = [];
+
+messageHandlers[messageSync] = (
+  encoder,
+  decoder,
+  provider,
+  emitSynced,
+  _messageType
+) => {
+  encoding__namespace.writeVarUint(encoder, messageSync);
+  const syncMessageType = syncProtocol__namespace.readSyncMessage(
+    decoder,
+    encoder,
+    provider.doc,
+    provider
+  );
+  if (
+    emitSynced && syncMessageType === syncProtocol__namespace.messageYjsSyncStep2 &&
+    !provider.synced
+  ) {
+    provider.synced = true;
+  }
+};
+
+messageHandlers[messageQueryAwareness] = (
+  encoder,
+  _decoder,
+  provider,
+  _emitSynced,
+  _messageType
+) => {
+  encoding__namespace.writeVarUint(encoder, messageAwareness);
+  encoding__namespace.writeVarUint8Array(
+    encoder,
+    awarenessProtocol__namespace.encodeAwarenessUpdate(
+      provider.awareness,
+      Array.from(provider.awareness.getStates().keys())
+    )
+  );
+};
+
+messageHandlers[messageAwareness] = (
+  _encoder,
+  decoder,
+  provider,
+  _emitSynced,
+  _messageType
+) => {
+  awarenessProtocol__namespace.applyAwarenessUpdate(
+    provider.awareness,
+    decoding__namespace.readVarUint8Array(decoder),
+    provider
+  );
+};
+
+messageHandlers[messageAuth] = (
+  _encoder,
+  decoder,
+  provider,
+  _emitSynced,
+  _messageType
+) => {
+  authProtocol__namespace.readAuthMessage(
+    decoder,
+    provider.doc,
+    (_ydoc, reason) => permissionDeniedHandler(provider, reason)
+  );
+};
+
+// @todo - this should depend on awareness.outdatedTime
+const messageReconnectTimeout = 30000;
+
+/**
+ * @param {WebsocketProvider} provider
+ * @param {string} reason
+ */
+const permissionDeniedHandler = (provider, reason) =>
+  console.warn(`Permission denied to access ${provider.url}.\n${reason}`);
+
+/**
+ * @param {WebsocketProvider} provider
+ * @param {Uint8Array} buf
+ * @param {boolean} emitSynced
+ * @return {encoding.Encoder}
+ */
+const readMessage = (provider, buf, emitSynced) => {
+  const decoder = decoding__namespace.createDecoder(buf);
+  const encoder = encoding__namespace.createEncoder();
+  const messageType = decoding__namespace.readVarUint(decoder);
+  const messageHandler = provider.messageHandlers[messageType];
+  if (/** @type {any} */ (messageHandler)) {
+    messageHandler(encoder, decoder, provider, emitSynced, messageType);
+  } else {
+    console.error('Unable to compute message');
+  }
+  return encoder
+};
+
+/**
+ * @param {WebsocketProvider} provider
+ */
+const setupWS = (provider) => {
+  if (provider.shouldConnect && provider.ws === null) {
+    const websocket = new provider._WS(provider.url);
+    websocket.binaryType = 'arraybuffer';
+    provider.ws = websocket;
+    provider.wsconnecting = true;
+    provider.wsconnected = false;
+    provider.synced = false;
+
+    websocket.onmessage = (event) => {
+      provider.wsLastMessageReceived = time__namespace.getUnixTime();
+      const encoder = readMessage(provider, new Uint8Array(event.data), true);
+      if (encoding__namespace.length(encoder) > 1) {
+        websocket.send(encoding__namespace.toUint8Array(encoder));
+      }
+    };
+    websocket.onerror = (event) => {
+      provider.emit('connection-error', [event, provider]);
+    };
+    websocket.onclose = (event) => {
+      provider.emit('connection-close', [event, provider]);
+      provider.ws = null;
+      provider.wsconnecting = false;
+      if (provider.wsconnected) {
+        provider.wsconnected = false;
+        provider.synced = false;
+        // update awareness (all users except local left)
+        awarenessProtocol__namespace.removeAwarenessStates(
+          provider.awareness,
+          Array.from(provider.awareness.getStates().keys()).filter((client) =>
+            client !== provider.doc.clientID
+          ),
+          provider
+        );
+        provider.emit('status', [{
+          status: 'disconnected'
+        }]);
+      } else {
+        provider.wsUnsuccessfulReconnects++;
+      }
+      // Start with no reconnect timeout and increase timeout by
+      // using exponential backoff starting with 100ms
+      setTimeout(
+        setupWS,
+        math__namespace.min(
+          math__namespace.pow(2, provider.wsUnsuccessfulReconnects) * 100,
+          provider.maxBackoffTime
+        ),
+        provider
+      );
+    };
+    websocket.onopen = () => {
+      provider.wsLastMessageReceived = time__namespace.getUnixTime();
+      provider.wsconnecting = false;
+      provider.wsconnected = true;
+      provider.wsUnsuccessfulReconnects = 0;
+      provider.emit('status', [{
+        status: 'connected'
+      }]);
+      // always send sync step 1 when connected
+      const encoder = encoding__namespace.createEncoder();
+      encoding__namespace.writeVarUint(encoder, messageSync);
+      syncProtocol__namespace.writeSyncStep1(encoder, provider.doc);
+      websocket.send(encoding__namespace.toUint8Array(encoder));
+      // broadcast local awareness state
+      if (provider.awareness.getLocalState() !== null) {
+        const encoderAwarenessState = encoding__namespace.createEncoder();
+        encoding__namespace.writeVarUint(encoderAwarenessState, messageAwareness);
+        encoding__namespace.writeVarUint8Array(
+          encoderAwarenessState,
+          awarenessProtocol__namespace.encodeAwarenessUpdate(provider.awareness, [
+            provider.doc.clientID
+          ])
+        );
+        websocket.send(encoding__namespace.toUint8Array(encoderAwarenessState));
+      }
+    };
+    provider.emit('status', [{
+      status: 'connecting'
+    }]);
+  }
+};
+
+/**
+ * @param {WebsocketProvider} provider
+ * @param {ArrayBuffer} buf
+ */
+const broadcastMessage = (provider, buf) => {
+  const ws = provider.ws;
+  if (provider.wsconnected && ws && ws.readyState === ws.OPEN) {
+    ws.send(buf);
+  }
+  if (provider.bcconnected) {
+    bc__namespace.publish(provider.bcChannel, buf, provider);
+  }
+};
+
+/**
+ * Websocket Provider for Yjs. Creates a websocket connection to sync the shared document.
+ * The document name is attached to the provided url. I.e. the following example
+ * creates a websocket connection to http://localhost:1234/my-document-name
+ *
+ * @example
+ *   import * as Y from 'yjs'
+ *   import { WebsocketProvider } from 'y-websocket'
+ *   const doc = new Y.Doc()
+ *   const provider = new WebsocketProvider('http://localhost:1234', 'my-document-name', doc)
+ *
+ * @extends {Observable<string>}
+ */
+class WebsocketProvider extends observable.Observable {
+  /**
+   * @param {string} serverUrl
+   * @param {string} roomname
+   * @param {Y.Doc} doc
+   * @param {object} opts
+   * @param {boolean} [opts.connect]
+   * @param {awarenessProtocol.Awareness} [opts.awareness]
+   * @param {Object<string,string>} [opts.params]
+   * @param {typeof WebSocket} [opts.WebSocketPolyfill] Optionall provide a WebSocket polyfill
+   * @param {number} [opts.resyncInterval] Request server state every `resyncInterval` milliseconds
+   * @param {number} [opts.maxBackoffTime] Maximum amount of time to wait before trying to reconnect (we try to reconnect using exponential backoff)
+   * @param {boolean} [opts.disableBc] Disable cross-tab BroadcastChannel communication
+   */
+  constructor (serverUrl, roomname, doc, {
+    connect = true,
+    awareness = new awarenessProtocol__namespace.Awareness(doc),
+    params = {},
+    WebSocketPolyfill = WebSocket,
+    resyncInterval = -1,
+    maxBackoffTime = 2500,
+    disableBc = false
+  } = {}) {
+    super();
+    // ensure that url is always ends with /
+    while (serverUrl[serverUrl.length - 1] === '/') {
+      serverUrl = serverUrl.slice(0, serverUrl.length - 1);
+    }
+    const encodedParams = url__namespace.encodeQueryParams(params);
+    this.maxBackoffTime = maxBackoffTime;
+    this.bcChannel = serverUrl + '/' + roomname;
+    this.url = serverUrl + '/' + roomname +
+      (encodedParams.length === 0 ? '' : '?' + encodedParams);
+    this.roomname = roomname;
+    this.doc = doc;
+    this._WS = WebSocketPolyfill;
+    this.awareness = awareness;
+    this.wsconnected = false;
+    this.wsconnecting = false;
+    this.bcconnected = false;
+    this.disableBc = disableBc;
+    this.wsUnsuccessfulReconnects = 0;
+    this.messageHandlers = messageHandlers.slice();
+    /**
+     * @type {boolean}
+     */
+    this._synced = false;
+    /**
+     * @type {WebSocket?}
+     */
+    this.ws = null;
+    this.wsLastMessageReceived = 0;
+    /**
+     * Whether to connect to other peers or not
+     * @type {boolean}
+     */
+    this.shouldConnect = connect;
+
+    /**
+     * @type {number}
+     */
+    this._resyncInterval = 0;
+    if (resyncInterval > 0) {
+      this._resyncInterval = /** @type {any} */ (setInterval(() => {
+        if (this.ws && this.ws.readyState === WebSocket.OPEN) {
+          // resend sync step 1
+          const encoder = encoding__namespace.createEncoder();
+          encoding__namespace.writeVarUint(encoder, messageSync);
+          syncProtocol__namespace.writeSyncStep1(encoder, doc);
+          this.ws.send(encoding__namespace.toUint8Array(encoder));
+        }
+      }, resyncInterval));
+    }
+
+    /**
+     * @param {ArrayBuffer} data
+     * @param {any} origin
+     */
+    this._bcSubscriber = (data, origin) => {
+      if (origin !== this) {
+        const encoder = readMessage(this, new Uint8Array(data), false);
+        if (encoding__namespace.length(encoder) > 1) {
+          bc__namespace.publish(this.bcChannel, encoding__namespace.toUint8Array(encoder), this);
+        }
+      }
+    };
+    /**
+     * Listens to Yjs updates and sends them to remote peers (ws and broadcastchannel)
+     * @param {Uint8Array} update
+     * @param {any} origin
+     */
+    this._updateHandler = (update, origin) => {
+      if (origin !== this) {
+        const encoder = encoding__namespace.createEncoder();
+        encoding__namespace.writeVarUint(encoder, messageSync);
+        syncProtocol__namespace.writeUpdate(encoder, update);
+        broadcastMessage(this, encoding__namespace.toUint8Array(encoder));
+      }
+    };
+    this.doc.on('update', this._updateHandler);
+    /**
+     * @param {any} changed
+     * @param {any} _origin
+     */
+    this._awarenessUpdateHandler = ({ added, updated, removed }, _origin) => {
+      const changedClients = added.concat(updated).concat(removed);
+      const encoder = encoding__namespace.createEncoder();
+      encoding__namespace.writeVarUint(encoder, messageAwareness);
+      encoding__namespace.writeVarUint8Array(
+        encoder,
+        awarenessProtocol__namespace.encodeAwarenessUpdate(awareness, changedClients)
+      );
+      broadcastMessage(this, encoding__namespace.toUint8Array(encoder));
+    };
+    this._exitHandler = () => {
+      awarenessProtocol__namespace.removeAwarenessStates(
+        this.awareness,
+        [doc.clientID],
+        'app closed'
+      );
+    };
+    if (env__namespace.isNode && typeof process !== 'undefined') {
+      process.on('exit', this._exitHandler);
+    }
+    awareness.on('update', this._awarenessUpdateHandler);
+    this._checkInterval = /** @type {any} */ (setInterval(() => {
+      if (
+        this.wsconnected &&
+        messageReconnectTimeout <
+          time__namespace.getUnixTime() - this.wsLastMessageReceived
+      ) {
+        // no message received in a long time - not even your own awareness
+        // updates (which are updated every 15 seconds)
+        /** @type {WebSocket} */ (this.ws).close();
+      }
+    }, messageReconnectTimeout / 10));
+    if (connect) {
+      this.connect();
+    }
+  }
+
+  /**
+   * @type {boolean}
+   */
+  get synced () {
+    return this._synced
+  }
+
+  set synced (state) {
+    if (this._synced !== state) {
+      this._synced = state;
+      this.emit('synced', [state]);
+      this.emit('sync', [state]);
+    }
+  }
+
+  destroy () {
+    if (this._resyncInterval !== 0) {
+      clearInterval(this._resyncInterval);
+    }
+    clearInterval(this._checkInterval);
+    this.disconnect();
+    if (env__namespace.isNode && typeof process !== 'undefined') {
+      process.off('exit', this._exitHandler);
+    }
+    this.awareness.off('update', this._awarenessUpdateHandler);
+    this.doc.off('update', this._updateHandler);
+    super.destroy();
+  }
+
+  connectBc () {
+    if (this.disableBc) {
+      return
+    }
+    if (!this.bcconnected) {
+      bc__namespace.subscribe(this.bcChannel, this._bcSubscriber);
+      this.bcconnected = true;
+    }
+    // send sync step1 to bc
+    // write sync step 1
+    const encoderSync = encoding__namespace.createEncoder();
+    encoding__namespace.writeVarUint(encoderSync, messageSync);
+    syncProtocol__namespace.writeSyncStep1(encoderSync, this.doc);
+    bc__namespace.publish(this.bcChannel, encoding__namespace.toUint8Array(encoderSync), this);
+    // broadcast local state
+    const encoderState = encoding__namespace.createEncoder();
+    encoding__namespace.writeVarUint(encoderState, messageSync);
+    syncProtocol__namespace.writeSyncStep2(encoderState, this.doc);
+    bc__namespace.publish(this.bcChannel, encoding__namespace.toUint8Array(encoderState), this);
+    // write queryAwareness
+    const encoderAwarenessQuery = encoding__namespace.createEncoder();
+    encoding__namespace.writeVarUint(encoderAwarenessQuery, messageQueryAwareness);
+    bc__namespace.publish(
+      this.bcChannel,
+      encoding__namespace.toUint8Array(encoderAwarenessQuery),
+      this
+    );
+    // broadcast local awareness state
+    const encoderAwarenessState = encoding__namespace.createEncoder();
+    encoding__namespace.writeVarUint(encoderAwarenessState, messageAwareness);
+    encoding__namespace.writeVarUint8Array(
+      encoderAwarenessState,
+      awarenessProtocol__namespace.encodeAwarenessUpdate(this.awareness, [
+        this.doc.clientID
+      ])
+    );
+    bc__namespace.publish(
+      this.bcChannel,
+      encoding__namespace.toUint8Array(encoderAwarenessState),
+      this
+    );
+  }
+
+  disconnectBc () {
+    // broadcast message with local awareness state set to null (indicating disconnect)
+    const encoder = encoding__namespace.createEncoder();
+    encoding__namespace.writeVarUint(encoder, messageAwareness);
+    encoding__namespace.writeVarUint8Array(
+      encoder,
+      awarenessProtocol__namespace.encodeAwarenessUpdate(this.awareness, [
+        this.doc.clientID
+      ], new Map())
+    );
+    broadcastMessage(this, encoding__namespace.toUint8Array(encoder));
+    if (this.bcconnected) {
+      bc__namespace.unsubscribe(this.bcChannel, this._bcSubscriber);
+      this.bcconnected = false;
+    }
+  }
+
+  disconnect () {
+    this.shouldConnect = false;
+    this.disconnectBc();
+    if (this.ws !== null) {
+      this.ws.close();
+    }
+  }
+
+  connect () {
+    this.shouldConnect = true;
+    if (!this.wsconnected && this.ws === null) {
+      setupWS(this);
+      this.connectBc();
+    }
+  }
+}
+
+exports.WebsocketProvider = WebsocketProvider;
+exports.messageAuth = messageAuth;
+exports.messageAwareness = messageAwareness;
+exports.messageQueryAwareness = messageQueryAwareness;
+exports.messageSync = messageSync;
+//# sourceMappingURL=y-websocket.cjs.map

node_modules/y-websocket/node_modules/ws/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2011 Einar Otto Stangvik <einaros@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

node_modules/y-websocket/node_modules/ws/README.md

@@ -0,0 +1,449 @@
+# ws: a Node.js WebSocket library
+
+[![Version npm](https://img.shields.io/npm/v/ws.svg?logo=npm)](https://www.npmjs.com/package/ws)
+[![Linux Build](https://img.shields.io/travis/websockets/ws/master.svg?logo=travis)](https://travis-ci.org/websockets/ws)
+[![Windows Build](https://img.shields.io/appveyor/ci/lpinca/ws/master.svg?logo=appveyor)](https://ci.appveyor.com/project/lpinca/ws)
+[![Coverage Status](https://img.shields.io/coveralls/websockets/ws/master.svg)](https://coveralls.io/github/websockets/ws)
+
+ws is a simple to use, blazing fast, and thoroughly tested WebSocket client and
+server implementation.
+
+Passes the quite extensive Autobahn test suite: [server][server-report],
+[client][client-report].
+
+**Note**: This module does not work in the browser. The client in the docs is a
+reference to a back end with the role of a client in the WebSocket
+communication. Browser clients must use the native
+[`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket)
+object. To make the same code work seamlessly on Node.js and the browser, you
+can use one of the many wrappers available on npm, like
+[isomorphic-ws](https://github.com/heineiuo/isomorphic-ws).
+
+## Table of Contents
+
+- [Protocol support](#protocol-support)
+- [Installing](#installing)
+  - [Opt-in for performance and spec compliance](#opt-in-for-performance-and-spec-compliance)
+- [API docs](#api-docs)
+- [WebSocket compression](#websocket-compression)
+- [Usage examples](#usage-examples)
+  - [Sending and receiving text data](#sending-and-receiving-text-data)
+  - [Sending binary data](#sending-binary-data)
+  - [Simple server](#simple-server)
+  - [External HTTP/S server](#external-https-server)
+  - [Multiple servers sharing a single HTTP/S server](#multiple-servers-sharing-a-single-https-server)
+  - [Server broadcast](#server-broadcast)
+  - [echo.websocket.org demo](#echowebsocketorg-demo)
+  - [Other examples](#other-examples)
+- [Error handling best practices](#error-handling-best-practices)
+- [FAQ](#faq)
+  - [How to get the IP address of the client?](#how-to-get-the-ip-address-of-the-client)
+  - [How to detect and close broken connections?](#how-to-detect-and-close-broken-connections)
+  - [How to connect via a proxy?](#how-to-connect-via-a-proxy)
+- [Changelog](#changelog)
+- [License](#license)
+
+## Protocol support
+
+- **HyBi drafts 07-12** (Use the option `protocolVersion: 8`)
+- **HyBi drafts 13-17** (Current default, alternatively option
+  `protocolVersion: 13`)
+
+## Installing
+
+```
+npm install ws
+```
+
+### Opt-in for performance and spec compliance
+
+There are 2 optional modules that can be installed along side with the ws
+module. These modules are binary addons which improve certain operations.
+Prebuilt binaries are available for the most popular platforms so you don't
+necessarily need to have a C++ compiler installed on your machine.
+
+- `npm install --save-optional bufferutil`: Allows to efficiently perform
+  operations such as masking and unmasking the data payload of the WebSocket
+  frames.
+- `npm install --save-optional utf-8-validate`: Allows to efficiently check if a
+  message contains valid UTF-8 as required by the spec.
+
+## API docs
+
+See [`/doc/ws.md`](./doc/ws.md) for Node.js-like docs for the ws classes.
+
+## WebSocket compression
+
+ws supports the [permessage-deflate extension][permessage-deflate] which enables
+the client and server to negotiate a compression algorithm and its parameters,
+and then selectively apply it to the data payloads of each WebSocket message.
+
+The extension is disabled by default on the server and enabled by default on the
+client. It adds a significant overhead in terms of performance and memory
+consumption so we suggest to enable it only if it is really needed.
+
+Note that Node.js has a variety of issues with high-performance compression,
+where increased concurrency, especially on Linux, can lead to [catastrophic
+memory fragmentation][node-zlib-bug] and slow performance. If you intend to use
+permessage-deflate in production, it is worthwhile to set up a test
+representative of your workload and ensure Node.js/zlib will handle it with
+acceptable performance and memory usage.
+
+Tuning of permessage-deflate can be done via the options defined below. You can
+also use `zlibDeflateOptions` and `zlibInflateOptions`, which is passed directly
+into the creation of [raw deflate/inflate streams][node-zlib-deflaterawdocs].
+
+See [the docs][ws-server-options] for more options.
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({
+  port: 8080,
+  perMessageDeflate: {
+    zlibDeflateOptions: {
+      // See zlib defaults.
+      chunkSize: 1024,
+      memLevel: 7,
+      level: 3
+    },
+    zlibInflateOptions: {
+      chunkSize: 10 * 1024
+    },
+    // Other options settable:
+    clientNoContextTakeover: true, // Defaults to negotiated value.
+    serverNoContextTakeover: true, // Defaults to negotiated value.
+    serverMaxWindowBits: 10, // Defaults to negotiated value.
+    // Below options specified as default values.
+    concurrencyLimit: 10, // Limits zlib concurrency for perf.
+    threshold: 1024 // Size (in bytes) below which messages
+    // should not be compressed.
+  }
+});
+```
+
+The client will only use the extension if it is supported and enabled on the
+server. To always disable the extension on the client set the
+`perMessageDeflate` option to `false`.
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('ws://www.host.com/path', {
+  perMessageDeflate: false
+});
+```
+
+## Usage examples
+
+### Sending and receiving text data
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('open', function open() {
+  ws.send('something');
+});
+
+ws.on('message', function incoming(data) {
+  console.log(data);
+});
+```
+
+### Sending binary data
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('open', function open() {
+  const array = new Float32Array(5);
+
+  for (var i = 0; i < array.length; ++i) {
+    array[i] = i / 2;
+  }
+
+  ws.send(array);
+});
+```
+
+### Simple server
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('message', function incoming(message) {
+    console.log('received: %s', message);
+  });
+
+  ws.send('something');
+});
+```
+
+### External HTTP/S server
+
+```js
+const fs = require('fs');
+const https = require('https');
+const WebSocket = require('ws');
+
+const server = new https.createServer({
+  cert: fs.readFileSync('/path/to/cert.pem'),
+  key: fs.readFileSync('/path/to/key.pem')
+});
+const wss = new WebSocket.Server({ server });
+
+wss.on('connection', function connection(ws) {
+  ws.on('message', function incoming(message) {
+    console.log('received: %s', message);
+  });
+
+  ws.send('something');
+});
+
+server.listen(8080);
+```
+
+### Multiple servers sharing a single HTTP/S server
+
+```js
+const http = require('http');
+const WebSocket = require('ws');
+
+const server = http.createServer();
+const wss1 = new WebSocket.Server({ noServer: true });
+const wss2 = new WebSocket.Server({ noServer: true });
+
+wss1.on('connection', function connection(ws) {
+  // ...
+});
+
+wss2.on('connection', function connection(ws) {
+  // ...
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+  const pathname = url.parse(request.url).pathname;
+
+  if (pathname === '/foo') {
+    wss1.handleUpgrade(request, socket, head, function done(ws) {
+      wss1.emit('connection', ws, request);
+    });
+  } else if (pathname === '/bar') {
+    wss2.handleUpgrade(request, socket, head, function done(ws) {
+      wss2.emit('connection', ws, request);
+    });
+  } else {
+    socket.destroy();
+  }
+});
+
+server.listen(8080);
+```
+
+### Server broadcast
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+// Broadcast to all.
+wss.broadcast = function broadcast(data) {
+  wss.clients.forEach(function each(client) {
+    if (client.readyState === WebSocket.OPEN) {
+      client.send(data);
+    }
+  });
+};
+
+wss.on('connection', function connection(ws) {
+  ws.on('message', function incoming(data) {
+    // Broadcast to everyone else.
+    wss.clients.forEach(function each(client) {
+      if (client !== ws && client.readyState === WebSocket.OPEN) {
+        client.send(data);
+      }
+    });
+  });
+});
+```
+
+### echo.websocket.org demo
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('wss://echo.websocket.org/', {
+  origin: 'https://websocket.org'
+});
+
+ws.on('open', function open() {
+  console.log('connected');
+  ws.send(Date.now());
+});
+
+ws.on('close', function close() {
+  console.log('disconnected');
+});
+
+ws.on('message', function incoming(data) {
+  console.log(`Roundtrip time: ${Date.now() - data} ms`);
+
+  setTimeout(function timeout() {
+    ws.send(Date.now());
+  }, 500);
+});
+```
+
+### Other examples
+
+For a full example with a browser client communicating with a ws server, see the
+examples folder.
+
+Otherwise, see the test cases.
+
+## Error handling best practices
+
+```js
+// If the WebSocket is closed before the following send is attempted
+ws.send('something');
+
+// Errors (both immediate and async write errors) can be detected in an optional
+// callback. The callback is also the only way of being notified that data has
+// actually been sent.
+ws.send('something', function ack(error) {
+  // If error is not defined, the send has been completed, otherwise the error
+  // object will indicate what failed.
+});
+
+// Immediate errors can also be handled with `try...catch`, but **note** that
+// since sends are inherently asynchronous, socket write failures will *not* be
+// captured when this technique is used.
+try {
+  ws.send('something');
+} catch (e) {
+  /* handle error */
+}
+```
+
+## FAQ
+
+### How to get the IP address of the client?
+
+The remote IP address can be obtained from the raw socket.
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', function connection(ws, req) {
+  const ip = req.connection.remoteAddress;
+});
+```
+
+When the server runs behind a proxy like NGINX, the de-facto standard is to use
+the `X-Forwarded-For` header.
+
+```js
+wss.on('connection', function connection(ws, req) {
+  const ip = req.headers['x-forwarded-for'].split(/\s*,\s*/)[0];
+});
+```
+
+### How to detect and close broken connections?
+
+Sometimes the link between the server and the client can be interrupted in a way
+that keeps both the server and the client unaware of the broken state of the
+connection (e.g. when pulling the cord).
+
+In these cases ping messages can be used as a means to verify that the remote
+endpoint is still responsive.
+
+```js
+const WebSocket = require('ws');
+
+function noop() {}
+
+function heartbeat() {
+  this.isAlive = true;
+}
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.isAlive = true;
+  ws.on('pong', heartbeat);
+});
+
+const interval = setInterval(function ping() {
+  wss.clients.forEach(function each(ws) {
+    if (ws.isAlive === false) return ws.terminate();
+
+    ws.isAlive = false;
+    ws.ping(noop);
+  });
+}, 30000);
+```
+
+Pong messages are automatically sent in response to ping messages as required by
+the spec.
+
+Just like the server example above your clients might as well lose connection
+without knowing it. You might want to add a ping listener on your clients to
+prevent that. A simple implementation would be:
+
+```js
+const WebSocket = require('ws');
+
+function heartbeat() {
+  clearTimeout(this.pingTimeout);
+
+  // Use `WebSocket#terminate()` and not `WebSocket#close()`. Delay should be
+  // equal to the interval at which your server sends out pings plus a
+  // conservative assumption of the latency.
+  this.pingTimeout = setTimeout(() => {
+    this.terminate();
+  }, 30000 + 1000);
+}
+
+const client = new WebSocket('wss://echo.websocket.org/');
+
+client.on('open', heartbeat);
+client.on('ping', heartbeat);
+client.on('close', function clear() {
+  clearTimeout(this.pingTimeout);
+});
+```
+
+### How to connect via a proxy?
+
+Use a custom `http.Agent` implementation like [https-proxy-agent][] or
+[socks-proxy-agent][].
+
+## Changelog
+
+We're using the GitHub [releases][changelog] for changelog entries.
+
+## License
+
+[MIT](LICENSE)
+
+[https-proxy-agent]: https://github.com/TooTallNate/node-https-proxy-agent
+[socks-proxy-agent]: https://github.com/TooTallNate/node-socks-proxy-agent
+[client-report]: http://websockets.github.io/ws/autobahn/clients/
+[server-report]: http://websockets.github.io/ws/autobahn/servers/
+[permessage-deflate]: https://tools.ietf.org/html/rfc7692
+[changelog]: https://github.com/websockets/ws/releases
+[node-zlib-bug]: https://github.com/nodejs/node/issues/8871
+[node-zlib-deflaterawdocs]:
+  https://nodejs.org/api/zlib.html#zlib_zlib_createdeflateraw_options
+[ws-server-options]:
+  https://github.com/websockets/ws/blob/master/doc/ws.md#new-websocketserveroptions-callback

node_modules/y-websocket/node_modules/ws/browser.js

@@ -0,0 +1,8 @@
+'use strict';
+
+module.exports = function() {
+  throw new Error(
+    'ws does not work in the browser. Browser clients must use the native ' +
+      'WebSocket object'
+  );
+};

node_modules/y-websocket/node_modules/ws/index.js

@@ -0,0 +1,9 @@
+'use strict';
+
+const WebSocket = require('./lib/websocket');
+
+WebSocket.Server = require('./lib/websocket-server');
+WebSocket.Receiver = require('./lib/receiver');
+WebSocket.Sender = require('./lib/sender');
+
+module.exports = WebSocket;

node_modules/y-websocket/node_modules/ws/lib/buffer-util.js

@@ -0,0 +1,144 @@
+'use strict';
+
+const { EMPTY_BUFFER } = require('./constants');
+
+/**
+ * Merges an array of buffers into a new buffer.
+ *
+ * @param {Buffer[]} list The array of buffers to concat
+ * @param {Number} totalLength The total length of buffers in the list
+ * @return {Buffer} The resulting buffer
+ * @public
+ */
+function concat(list, totalLength) {
+  if (list.length === 0) return EMPTY_BUFFER;
+  if (list.length === 1) return list[0];
+
+  const target = Buffer.allocUnsafe(totalLength);
+  var offset = 0;
+
+  for (var i = 0; i < list.length; i++) {
+    const buf = list[i];
+    buf.copy(target, offset);
+    offset += buf.length;
+  }
+
+  return target;
+}
+
+/**
+ * Masks a buffer using the given mask.
+ *
+ * @param {Buffer} source The buffer to mask
+ * @param {Buffer} mask The mask to use
+ * @param {Buffer} output The buffer where to store the result
+ * @param {Number} offset The offset at which to start writing
+ * @param {Number} length The number of bytes to mask.
+ * @public
+ */
+function _mask(source, mask, output, offset, length) {
+  for (var i = 0; i < length; i++) {
+    output[offset + i] = source[i] ^ mask[i & 3];
+  }
+}
+
+/**
+ * Unmasks a buffer using the given mask.
+ *
+ * @param {Buffer} buffer The buffer to unmask
+ * @param {Buffer} mask The mask to use
+ * @public
+ */
+function _unmask(buffer, mask) {
+  // Required until https://github.com/nodejs/node/issues/9006 is resolved.
+  const length = buffer.length;
+  for (var i = 0; i < length; i++) {
+    buffer[i] ^= mask[i & 3];
+  }
+}
+
+/**
+ * Converts a buffer to an `ArrayBuffer`.
+ *
+ * @param {Buffer} buf The buffer to convert
+ * @return {ArrayBuffer} Converted buffer
+ * @public
+ */
+function toArrayBuffer(buf) {
+  if (buf.byteLength === buf.buffer.byteLength) {
+    return buf.buffer;
+  }
+
+  return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
+}
+
+/**
+ * Converts `data` to a `Buffer`.
+ *
+ * @param {*} data The data to convert
+ * @return {Buffer} The buffer
+ * @throws {TypeError}
+ * @public
+ */
+function toBuffer(data) {
+  toBuffer.readOnly = true;
+
+  if (Buffer.isBuffer(data)) return data;
+
+  var buf;
+
+  if (data instanceof ArrayBuffer) {
+    buf = Buffer.from(data);
+  } else if (ArrayBuffer.isView(data)) {
+    buf = viewToBuffer(data);
+  } else {
+    buf = Buffer.from(data);
+    toBuffer.readOnly = false;
+  }
+
+  return buf;
+}
+
+/**
+ * Converts an `ArrayBuffer` view into a buffer.
+ *
+ * @param {(DataView|TypedArray)} view The view to convert
+ * @return {Buffer} Converted view
+ * @private
+ */
+function viewToBuffer(view) {
+  const buf = Buffer.from(view.buffer);
+
+  if (view.byteLength !== view.buffer.byteLength) {
+    return buf.slice(view.byteOffset, view.byteOffset + view.byteLength);
+  }
+
+  return buf;
+}
+
+try {
+  const bufferUtil = require('bufferutil');
+  const bu = bufferUtil.BufferUtil || bufferUtil;
+
+  module.exports = {
+    concat,
+    mask(source, mask, output, offset, length) {
+      if (length < 48) _mask(source, mask, output, offset, length);
+      else bu.mask(source, mask, output, offset, length);
+    },
+    toArrayBuffer,
+    toBuffer,
+    unmask(buffer, mask) {
+      if (buffer.length < 32) _unmask(buffer, mask);
+      else bu.unmask(buffer, mask);
+    }
+  };
+} catch (e) /* istanbul ignore next */ {
+  module.exports = {
+    concat,
+    mask: _mask,
+    toArrayBuffer,
+    toBuffer,
+    unmask: _unmask
+  };
+}

node_modules/y-websocket/node_modules/ws/lib/constants.js

@@ -0,0 +1,10 @@
+'use strict';
+
+module.exports = {
+  BINARY_TYPES: ['nodebuffer', 'arraybuffer', 'fragments'],
+  GUID: '258EAFA5-E914-47DA-95CA-C5AB0DC85B11',
+  kStatusCode: Symbol('status-code'),
+  kWebSocket: Symbol('websocket'),
+  EMPTY_BUFFER: Buffer.alloc(0),
+  NOOP: () => {}
+};

node_modules/y-websocket/node_modules/ws/lib/event-target.js

@@ -0,0 +1,170 @@
+'use strict';
+
+/**
+ * Class representing an event.
+ *
+ * @private
+ */
+class Event {
+  /**
+   * Create a new `Event`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} target A reference to the target to which the event was dispatched
+   */
+  constructor(type, target) {
+    this.target = target;
+    this.type = type;
+  }
+}
+
+/**
+ * Class representing a message event.
+ *
+ * @extends Event
+ * @private
+ */
+class MessageEvent extends Event {
+  /**
+   * Create a new `MessageEvent`.
+   *
+   * @param {(String|Buffer|ArrayBuffer|Buffer[])} data The received data
+   * @param {WebSocket} target A reference to the target to which the event was dispatched
+   */
+  constructor(data, target) {
+    super('message', target);
+
+    this.data = data;
+  }
+}
+
+/**
+ * Class representing a close event.
+ *
+ * @extends Event
+ * @private
+ */
+class CloseEvent extends Event {
+  /**
+   * Create a new `CloseEvent`.
+   *
+   * @param {Number} code The status code explaining why the connection is being closed
+   * @param {String} reason A human-readable string explaining why the connection is closing
+   * @param {WebSocket} target A reference to the target to which the event was dispatched
+   */
+  constructor(code, reason, target) {
+    super('close', target);
+
+    this.wasClean = target._closeFrameReceived && target._closeFrameSent;
+    this.reason = reason;
+    this.code = code;
+  }
+}
+
+/**
+ * Class representing an open event.
+ *
+ * @extends Event
+ * @private
+ */
+class OpenEvent extends Event {
+  /**
+   * Create a new `OpenEvent`.
+   *
+   * @param {WebSocket} target A reference to the target to which the event was dispatched
+   */
+  constructor(target) {
+    super('open', target);
+  }
+}
+
+/**
+ * Class representing an error event.
+ *
+ * @extends Event
+ * @private
+ */
+class ErrorEvent extends Event {
+  /**
+   * Create a new `ErrorEvent`.
+   *
+   * @param {Object} error The error that generated this event
+   * @param {WebSocket} target A reference to the target to which the event was dispatched
+   */
+  constructor(error, target) {
+    super('error', target);
+
+    this.message = error.message;
+    this.error = error;
+  }
+}
+
+/**
+ * This provides methods for emulating the `EventTarget` interface. It's not
+ * meant to be used directly.
+ *
+ * @mixin
+ */
+const EventTarget = {
+  /**
+   * Register an event listener.
+   *
+   * @param {String} method A string representing the event type to listen for
+   * @param {Function} listener The listener to add
+   * @public
+   */
+  addEventListener(method, listener) {
+    if (typeof listener !== 'function') return;
+
+    function onMessage(data) {
+      listener.call(this, new MessageEvent(data, this));
+    }
+
+    function onClose(code, message) {
+      listener.call(this, new CloseEvent(code, message, this));
+    }
+
+    function onError(error) {
+      listener.call(this, new ErrorEvent(error, this));
+    }
+
+    function onOpen() {
+      listener.call(this, new OpenEvent(this));
+    }
+
+    if (method === 'message') {
+      onMessage._listener = listener;
+      this.on(method, onMessage);
+    } else if (method === 'close') {
+      onClose._listener = listener;
+      this.on(method, onClose);
+    } else if (method === 'error') {
+      onError._listener = listener;
+      this.on(method, onError);
+    } else if (method === 'open') {
+      onOpen._listener = listener;
+      this.on(method, onOpen);
+    } else {
+      this.on(method, listener);
+    }
+  },
+
+  /**
+   * Remove an event listener.
+   *
+   * @param {String} method A string representing the event type to remove
+   * @param {Function} listener The listener to remove
+   * @public
+   */
+  removeEventListener(method, listener) {
+    const listeners = this.listeners(method);
+
+    for (var i = 0; i < listeners.length; i++) {
+      if (listeners[i] === listener || listeners[i]._listener === listener) {
+        this.removeListener(method, listeners[i]);
+      }
+    }
+  }
+};
+
+module.exports = EventTarget;

node_modules/y-websocket/node_modules/ws/lib/extension.js

@@ -0,0 +1,222 @@
+'use strict';
+
+//
+// Allowed token characters:
+//
+// '!', '#', '$', '%', '&', ''', '*', '+', '-',
+// '.', 0-9, A-Z, '^', '_', '`', a-z, '|', '~'
+//
+// tokenChars[32] === 0 // ' '
+// tokenChars[33] === 1 // '!'
+// tokenChars[34] === 0 // '"'
+// ...
+//
+// prettier-ignore
+const tokenChars = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 15
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
+  0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, // 32 - 47
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 48 - 63
+  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, // 80 - 95
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0 // 112 - 127
+];
+
+/**
+ * Adds an offer to the map of extension offers or a parameter to the map of
+ * parameters.
+ *
+ * @param {Object} dest The map of extension offers or parameters
+ * @param {String} name The extension or parameter name
+ * @param {(Object|Boolean|String)} elem The extension parameters or the
+ *     parameter value
+ * @private
+ */
+function push(dest, name, elem) {
+  if (Object.prototype.hasOwnProperty.call(dest, name)) dest[name].push(elem);
+  else dest[name] = [elem];
+}
+
+/**
+ * Parses the `Sec-WebSocket-Extensions` header into an object.
+ *
+ * @param {String} header The field value of the header
+ * @return {Object} The parsed object
+ * @public
+ */
+function parse(header) {
+  const offers = {};
+
+  if (header === undefined || header === '') return offers;
+
+  var params = {};
+  var mustUnescape = false;
+  var isEscaping = false;
+  var inQuotes = false;
+  var extensionName;
+  var paramName;
+  var start = -1;
+  var end = -1;
+
+  for (var i = 0; i < header.length; i++) {
+    const code = header.charCodeAt(i);
+
+    if (extensionName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (code === 0x20 /* ' ' */ || code === 0x09 /* '\t' */) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b /* ';' */ || code === 0x2c /* ',' */) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        const name = header.slice(start, end);
+        if (code === 0x2c) {
+          push(offers, name, params);
+          params = {};
+        } else {
+          extensionName = name;
+        }
+
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else if (paramName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (code === 0x20 || code === 0x09) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        push(params, header.slice(start, end), true);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = {};
+          extensionName = undefined;
+        }
+
+        start = end = -1;
+      } else if (code === 0x3d /* '=' */ && start !== -1 && end === -1) {
+        paramName = header.slice(start, i);
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else {
+      //
+      // The value of a quoted-string after unescaping must conform to the
+      // token ABNF, so only token characters are valid.
+      // Ref: https://tools.ietf.org/html/rfc6455#section-9.1
+      //
+      if (isEscaping) {
+        if (tokenChars[code] !== 1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+        if (start === -1) start = i;
+        else if (!mustUnescape) mustUnescape = true;
+        isEscaping = false;
+      } else if (inQuotes) {
+        if (tokenChars[code] === 1) {
+          if (start === -1) start = i;
+        } else if (code === 0x22 /* '"' */ && start !== -1) {
+          inQuotes = false;
+          end = i;
+        } else if (code === 0x5c /* '\' */) {
+          isEscaping = true;
+        } else {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+      } else if (code === 0x22 && header.charCodeAt(i - 1) === 0x3d) {
+        inQuotes = true;
+      } else if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (start !== -1 && (code === 0x20 || code === 0x09)) {
+        if (end === -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        var value = header.slice(start, end);
+        if (mustUnescape) {
+          value = value.replace(/\\/g, '');
+          mustUnescape = false;
+        }
+        push(params, paramName, value);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = {};
+          extensionName = undefined;
+        }
+
+        paramName = undefined;
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    }
+  }
+
+  if (start === -1 || inQuotes) {
+    throw new SyntaxError('Unexpected end of input');
+  }
+
+  if (end === -1) end = i;
+  const token = header.slice(start, end);
+  if (extensionName === undefined) {
+    push(offers, token, {});
+  } else {
+    if (paramName === undefined) {
+      push(params, token, true);
+    } else if (mustUnescape) {
+      push(params, paramName, token.replace(/\\/g, ''));
+    } else {
+      push(params, paramName, token);
+    }
+    push(offers, extensionName, params);
+  }
+
+  return offers;
+}
+
+/**
+ * Builds the `Sec-WebSocket-Extensions` header field value.
+ *
+ * @param {Object} extensions The map of extensions and parameters to format
+ * @return {String} A string representing the given object
+ * @public
+ */
+function format(extensions) {
+  return Object.keys(extensions)
+    .map((extension) => {
+      var configurations = extensions[extension];
+      if (!Array.isArray(configurations)) configurations = [configurations];
+      return configurations
+        .map((params) => {
+          return [extension]
+            .concat(
+              Object.keys(params).map((k) => {
+                var values = params[k];
+                if (!Array.isArray(values)) values = [values];
+                return values
+                  .map((v) => (v === true ? k : `${k}=${v}`))
+                  .join('; ');
+              })
+            )
+            .join('; ');
+        })
+        .join(', ');
+    })
+    .join(', ');
+}
+
+module.exports = { format, parse };

node_modules/y-websocket/node_modules/ws/lib/permessage-deflate.js

@@ -0,0 +1,502 @@
+'use strict';
+
+const Limiter = require('async-limiter');
+const zlib = require('zlib');
+
+const bufferUtil = require('./buffer-util');
+const { kStatusCode, NOOP } = require('./constants');
+
+const TRAILER = Buffer.from([0x00, 0x00, 0xff, 0xff]);
+const EMPTY_BLOCK = Buffer.from([0x00]);
+
+const kPerMessageDeflate = Symbol('permessage-deflate');
+const kTotalLength = Symbol('total-length');
+const kCallback = Symbol('callback');
+const kBuffers = Symbol('buffers');
+const kError = Symbol('error');
+
+//
+// We limit zlib concurrency, which prevents severe memory fragmentation
+// as documented in https://github.com/nodejs/node/issues/8871#issuecomment-250915913
+// and https://github.com/websockets/ws/issues/1202
+//
+// Intentionally global; it's the global thread pool that's an issue.
+//
+let zlibLimiter;
+
+/**
+ * permessage-deflate implementation.
+ */
+class PerMessageDeflate {
+  /**
+   * Creates a PerMessageDeflate instance.
+   *
+   * @param {Object} options Configuration options
+   * @param {Boolean} options.serverNoContextTakeover Request/accept disabling
+   *     of server context takeover
+   * @param {Boolean} options.clientNoContextTakeover Advertise/acknowledge
+   *     disabling of client context takeover
+   * @param {(Boolean|Number)} options.serverMaxWindowBits Request/confirm the
+   *     use of a custom server window size
+   * @param {(Boolean|Number)} options.clientMaxWindowBits Advertise support
+   *     for, or request, a custom client window size
+   * @param {Object} options.zlibDeflateOptions Options to pass to zlib on deflate
+   * @param {Object} options.zlibInflateOptions Options to pass to zlib on inflate
+   * @param {Number} options.threshold Size (in bytes) below which messages
+   *     should not be compressed
+   * @param {Number} options.concurrencyLimit The number of concurrent calls to
+   *     zlib
+   * @param {Boolean} isServer Create the instance in either server or client
+   *     mode
+   * @param {Number} maxPayload The maximum allowed message length
+   */
+  constructor(options, isServer, maxPayload) {
+    this._maxPayload = maxPayload | 0;
+    this._options = options || {};
+    this._threshold =
+      this._options.threshold !== undefined ? this._options.threshold : 1024;
+    this._isServer = !!isServer;
+    this._deflate = null;
+    this._inflate = null;
+
+    this.params = null;
+
+    if (!zlibLimiter) {
+      const concurrency =
+        this._options.concurrencyLimit !== undefined
+          ? this._options.concurrencyLimit
+          : 10;
+      zlibLimiter = new Limiter({ concurrency });
+    }
+  }
+
+  /**
+   * @type {String}
+   */
+  static get extensionName() {
+    return 'permessage-deflate';
+  }
+
+  /**
+   * Create an extension negotiation offer.
+   *
+   * @return {Object} Extension parameters
+   * @public
+   */
+  offer() {
+    const params = {};
+
+    if (this._options.serverNoContextTakeover) {
+      params.server_no_context_takeover = true;
+    }
+    if (this._options.clientNoContextTakeover) {
+      params.client_no_context_takeover = true;
+    }
+    if (this._options.serverMaxWindowBits) {
+      params.server_max_window_bits = this._options.serverMaxWindowBits;
+    }
+    if (this._options.clientMaxWindowBits) {
+      params.client_max_window_bits = this._options.clientMaxWindowBits;
+    } else if (this._options.clientMaxWindowBits == null) {
+      params.client_max_window_bits = true;
+    }
+
+    return params;
+  }
+
+  /**
+   * Accept an extension negotiation offer/response.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Object} Accepted configuration
+   * @public
+   */
+  accept(configurations) {
+    configurations = this.normalizeParams(configurations);
+
+    this.params = this._isServer
+      ? this.acceptAsServer(configurations)
+      : this.acceptAsClient(configurations);
+
+    return this.params;
+  }
+
+  /**
+   * Releases all resources used by the extension.
+   *
+   * @public
+   */
+  cleanup() {
+    if (this._inflate) {
+      this._inflate.close();
+      this._inflate = null;
+    }
+
+    if (this._deflate) {
+      this._deflate.close();
+      this._deflate = null;
+    }
+  }
+
+  /**
+   *  Accept an extension negotiation offer.
+   *
+   * @param {Array} offers The extension negotiation offers
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsServer(offers) {
+    const opts = this._options;
+    const accepted = offers.find((params) => {
+      if (
+        (opts.serverNoContextTakeover === false &&
+          params.server_no_context_takeover) ||
+        (params.server_max_window_bits &&
+          (opts.serverMaxWindowBits === false ||
+            (typeof opts.serverMaxWindowBits === 'number' &&
+              opts.serverMaxWindowBits > params.server_max_window_bits))) ||
+        (typeof opts.clientMaxWindowBits === 'number' &&
+          !params.client_max_window_bits)
+      ) {
+        return false;
+      }
+
+      return true;
+    });
+
+    if (!accepted) {
+      throw new Error('None of the extension offers can be accepted');
+    }
+
+    if (opts.serverNoContextTakeover) {
+      accepted.server_no_context_takeover = true;
+    }
+    if (opts.clientNoContextTakeover) {
+      accepted.client_no_context_takeover = true;
+    }
+    if (typeof opts.serverMaxWindowBits === 'number') {
+      accepted.server_max_window_bits = opts.serverMaxWindowBits;
+    }
+    if (typeof opts.clientMaxWindowBits === 'number') {
+      accepted.client_max_window_bits = opts.clientMaxWindowBits;
+    } else if (
+      accepted.client_max_window_bits === true ||
+      opts.clientMaxWindowBits === false
+    ) {
+      delete accepted.client_max_window_bits;
+    }
+
+    return accepted;
+  }
+
+  /**
+   * Accept the extension negotiation response.
+   *
+   * @param {Array} response The extension negotiation response
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsClient(response) {
+    const params = response[0];
+
+    if (
+      this._options.clientNoContextTakeover === false &&
+      params.client_no_context_takeover
+    ) {
+      throw new Error('Unexpected parameter "client_no_context_takeover"');
+    }
+
+    if (!params.client_max_window_bits) {
+      if (typeof this._options.clientMaxWindowBits === 'number') {
+        params.client_max_window_bits = this._options.clientMaxWindowBits;
+      }
+    } else if (
+      this._options.clientMaxWindowBits === false ||
+      (typeof this._options.clientMaxWindowBits === 'number' &&
+        params.client_max_window_bits > this._options.clientMaxWindowBits)
+    ) {
+      throw new Error(
+        'Unexpected or invalid parameter "client_max_window_bits"'
+      );
+    }
+
+    return params;
+  }
+
+  /**
+   * Normalize parameters.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Array} The offers/response with normalized parameters
+   * @private
+   */
+  normalizeParams(configurations) {
+    configurations.forEach((params) => {
+      Object.keys(params).forEach((key) => {
+        var value = params[key];
+
+        if (value.length > 1) {
+          throw new Error(`Parameter "${key}" must have only a single value`);
+        }
+
+        value = value[0];
+
+        if (key === 'client_max_window_bits') {
+          if (value !== true) {
+            const num = +value;
+            if (!Number.isInteger(num) || num < 8 || num > 15) {
+              throw new TypeError(
+                `Invalid value for parameter "${key}": ${value}`
+              );
+            }
+            value = num;
+          } else if (!this._isServer) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else if (key === 'server_max_window_bits') {
+          const num = +value;
+          if (!Number.isInteger(num) || num < 8 || num > 15) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+          value = num;
+        } else if (
+          key === 'client_no_context_takeover' ||
+          key === 'server_no_context_takeover'
+        ) {
+          if (value !== true) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else {
+          throw new Error(`Unknown parameter "${key}"`);
+        }
+
+        params[key] = value;
+      });
+    });
+
+    return configurations;
+  }
+
+  /**
+   * Decompress data. Concurrency limited by async-limiter.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  decompress(data, fin, callback) {
+    zlibLimiter.push((done) => {
+      this._decompress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Compress data. Concurrency limited by async-limiter.
+   *
+   * @param {Buffer} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  compress(data, fin, callback) {
+    zlibLimiter.push((done) => {
+      this._compress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Decompress data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _decompress(data, fin, callback) {
+    const endpoint = this._isServer ? 'client' : 'server';
+
+    if (!this._inflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._inflate = zlib.createInflateRaw(
+        Object.assign({}, this._options.zlibInflateOptions, { windowBits })
+      );
+      this._inflate[kPerMessageDeflate] = this;
+      this._inflate[kTotalLength] = 0;
+      this._inflate[kBuffers] = [];
+      this._inflate.on('error', inflateOnError);
+      this._inflate.on('data', inflateOnData);
+    }
+
+    this._inflate[kCallback] = callback;
+
+    this._inflate.write(data);
+    if (fin) this._inflate.write(TRAILER);
+
+    this._inflate.flush(() => {
+      const err = this._inflate[kError];
+
+      if (err) {
+        this._inflate.close();
+        this._inflate = null;
+        callback(err);
+        return;
+      }
+
+      const data = bufferUtil.concat(
+        this._inflate[kBuffers],
+        this._inflate[kTotalLength]
+      );
+
+      if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+        this._inflate.close();
+        this._inflate = null;
+      } else {
+        this._inflate[kTotalLength] = 0;
+        this._inflate[kBuffers] = [];
+      }
+
+      callback(null, data);
+    });
+  }
+
+  /**
+   * Compress data.
+   *
+   * @param {Buffer} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _compress(data, fin, callback) {
+    if (!data || data.length === 0) {
+      process.nextTick(callback, null, EMPTY_BLOCK);
+      return;
+    }
+
+    const endpoint = this._isServer ? 'server' : 'client';
+
+    if (!this._deflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._deflate = zlib.createDeflateRaw(
+        Object.assign({}, this._options.zlibDeflateOptions, { windowBits })
+      );
+
+      this._deflate[kTotalLength] = 0;
+      this._deflate[kBuffers] = [];
+
+      //
+      // An `'error'` event is emitted, only on Node.js < 10.0.0, if the
+      // `zlib.DeflateRaw` instance is closed while data is being processed.
+      // This can happen if `PerMessageDeflate#cleanup()` is called at the wrong
+      // time due to an abnormal WebSocket closure.
+      //
+      this._deflate.on('error', NOOP);
+      this._deflate.on('data', deflateOnData);
+    }
+
+    this._deflate.write(data);
+    this._deflate.flush(zlib.Z_SYNC_FLUSH, () => {
+      if (!this._deflate) {
+        //
+        // This `if` statement is only needed for Node.js < 10.0.0 because as of
+        // commit https://github.com/nodejs/node/commit/5e3f5164, the flush
+        // callback is no longer called if the deflate stream is closed while
+        // data is being processed.
+        //
+        return;
+      }
+
+      var data = bufferUtil.concat(
+        this._deflate[kBuffers],
+        this._deflate[kTotalLength]
+      );
+
+      if (fin) data = data.slice(0, data.length - 4);
+
+      if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+        this._deflate.close();
+        this._deflate = null;
+      } else {
+        this._deflate[kTotalLength] = 0;
+        this._deflate[kBuffers] = [];
+      }
+
+      callback(null, data);
+    });
+  }
+}
+
+module.exports = PerMessageDeflate;
+
+/**
+ * The listener of the `zlib.DeflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function deflateOnData(chunk) {
+  this[kBuffers].push(chunk);
+  this[kTotalLength] += chunk.length;
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function inflateOnData(chunk) {
+  this[kTotalLength] += chunk.length;
+
+  if (
+    this[kPerMessageDeflate]._maxPayload < 1 ||
+    this[kTotalLength] <= this[kPerMessageDeflate]._maxPayload
+  ) {
+    this[kBuffers].push(chunk);
+    return;
+  }
+
+  this[kError] = new RangeError('Max payload size exceeded');
+  this[kError][kStatusCode] = 1009;
+  this.removeListener('data', inflateOnData);
+  this.reset();
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'error'` event.
+ *
+ * @param {Error} err The emitted error
+ * @private
+ */
+function inflateOnError(err) {
+  //
+  // There is no need to call `Zlib#close()` as the handle is automatically
+  // closed when an error is emitted.
+  //
+  this[kPerMessageDeflate]._inflate = null;
+  err[kStatusCode] = 1007;
+  this[kCallback](err);
+}

node_modules/y-websocket/node_modules/ws/lib/receiver.js

@@ -0,0 +1,492 @@
+'use strict';
+
+const { Writable } = require('stream');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const {
+  BINARY_TYPES,
+  EMPTY_BUFFER,
+  kStatusCode,
+  kWebSocket
+} = require('./constants');
+const { concat, toArrayBuffer, unmask } = require('./buffer-util');
+const { isValidStatusCode, isValidUTF8 } = require('./validation');
+
+const GET_INFO = 0;
+const GET_PAYLOAD_LENGTH_16 = 1;
+const GET_PAYLOAD_LENGTH_64 = 2;
+const GET_MASK = 3;
+const GET_DATA = 4;
+const INFLATING = 5;
+
+/**
+ * HyBi Receiver implementation.
+ *
+ * @extends stream.Writable
+ */
+class Receiver extends Writable {
+  /**
+   * Creates a Receiver instance.
+   *
+   * @param {String} binaryType The type for binary data
+   * @param {Object} extensions An object containing the negotiated extensions
+   * @param {Number} maxPayload The maximum allowed message length
+   */
+  constructor(binaryType, extensions, maxPayload) {
+    super();
+
+    this._binaryType = binaryType || BINARY_TYPES[0];
+    this[kWebSocket] = undefined;
+    this._extensions = extensions || {};
+    this._maxPayload = maxPayload | 0;
+
+    this._bufferedBytes = 0;
+    this._buffers = [];
+
+    this._compressed = false;
+    this._payloadLength = 0;
+    this._mask = undefined;
+    this._fragmented = 0;
+    this._masked = false;
+    this._fin = false;
+    this._opcode = 0;
+
+    this._totalPayloadLength = 0;
+    this._messageLength = 0;
+    this._fragments = [];
+
+    this._state = GET_INFO;
+    this._loop = false;
+  }
+
+  /**
+   * Implements `Writable.prototype._write()`.
+   *
+   * @param {Buffer} chunk The chunk of data to write
+   * @param {String} encoding The character encoding of `chunk`
+   * @param {Function} cb Callback
+   */
+  _write(chunk, encoding, cb) {
+    if (this._opcode === 0x08 && this._state == GET_INFO) return cb();
+
+    this._bufferedBytes += chunk.length;
+    this._buffers.push(chunk);
+    this.startLoop(cb);
+  }
+
+  /**
+   * Consumes `n` bytes from the buffered data.
+   *
+   * @param {Number} n The number of bytes to consume
+   * @return {Buffer} The consumed bytes
+   * @private
+   */
+  consume(n) {
+    this._bufferedBytes -= n;
+
+    if (n === this._buffers[0].length) return this._buffers.shift();
+
+    if (n < this._buffers[0].length) {
+      const buf = this._buffers[0];
+      this._buffers[0] = buf.slice(n);
+      return buf.slice(0, n);
+    }
+
+    const dst = Buffer.allocUnsafe(n);
+
+    do {
+      const buf = this._buffers[0];
+
+      if (n >= buf.length) {
+        this._buffers.shift().copy(dst, dst.length - n);
+      } else {
+        buf.copy(dst, dst.length - n, 0, n);
+        this._buffers[0] = buf.slice(n);
+      }
+
+      n -= buf.length;
+    } while (n > 0);
+
+    return dst;
+  }
+
+  /**
+   * Starts the parsing loop.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  startLoop(cb) {
+    var err;
+    this._loop = true;
+
+    do {
+      switch (this._state) {
+        case GET_INFO:
+          err = this.getInfo();
+          break;
+        case GET_PAYLOAD_LENGTH_16:
+          err = this.getPayloadLength16();
+          break;
+        case GET_PAYLOAD_LENGTH_64:
+          err = this.getPayloadLength64();
+          break;
+        case GET_MASK:
+          this.getMask();
+          break;
+        case GET_DATA:
+          err = this.getData(cb);
+          break;
+        default:
+          // `INFLATING`
+          this._loop = false;
+          return;
+      }
+    } while (this._loop);
+
+    cb(err);
+  }
+
+  /**
+   * Reads the first two bytes of a frame.
+   *
+   * @return {(RangeError|undefined)} A possible error
+   * @private
+   */
+  getInfo() {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(2);
+
+    if ((buf[0] & 0x30) !== 0x00) {
+      this._loop = false;
+      return error(RangeError, 'RSV2 and RSV3 must be clear', true, 1002);
+    }
+
+    const compressed = (buf[0] & 0x40) === 0x40;
+
+    if (compressed && !this._extensions[PerMessageDeflate.extensionName]) {
+      this._loop = false;
+      return error(RangeError, 'RSV1 must be clear', true, 1002);
+    }
+
+    this._fin = (buf[0] & 0x80) === 0x80;
+    this._opcode = buf[0] & 0x0f;
+    this._payloadLength = buf[1] & 0x7f;
+
+    if (this._opcode === 0x00) {
+      if (compressed) {
+        this._loop = false;
+        return error(RangeError, 'RSV1 must be clear', true, 1002);
+      }
+
+      if (!this._fragmented) {
+        this._loop = false;
+        return error(RangeError, 'invalid opcode 0', true, 1002);
+      }
+
+      this._opcode = this._fragmented;
+    } else if (this._opcode === 0x01 || this._opcode === 0x02) {
+      if (this._fragmented) {
+        this._loop = false;
+        return error(RangeError, `invalid opcode ${this._opcode}`, true, 1002);
+      }
+
+      this._compressed = compressed;
+    } else if (this._opcode > 0x07 && this._opcode < 0x0b) {
+      if (!this._fin) {
+        this._loop = false;
+        return error(RangeError, 'FIN must be set', true, 1002);
+      }
+
+      if (compressed) {
+        this._loop = false;
+        return error(RangeError, 'RSV1 must be clear', true, 1002);
+      }
+
+      if (this._payloadLength > 0x7d) {
+        this._loop = false;
+        return error(
+          RangeError,
+          `invalid payload length ${this._payloadLength}`,
+          true,
+          1002
+        );
+      }
+    } else {
+      this._loop = false;
+      return error(RangeError, `invalid opcode ${this._opcode}`, true, 1002);
+    }
+
+    if (!this._fin && !this._fragmented) this._fragmented = this._opcode;
+    this._masked = (buf[1] & 0x80) === 0x80;
+
+    if (this._payloadLength === 126) this._state = GET_PAYLOAD_LENGTH_16;
+    else if (this._payloadLength === 127) this._state = GET_PAYLOAD_LENGTH_64;
+    else return this.haveLength();
+  }
+
+  /**
+   * Gets extended payload length (7+16).
+   *
+   * @return {(RangeError|undefined)} A possible error
+   * @private
+   */
+  getPayloadLength16() {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    this._payloadLength = this.consume(2).readUInt16BE(0);
+    return this.haveLength();
+  }
+
+  /**
+   * Gets extended payload length (7+64).
+   *
+   * @return {(RangeError|undefined)} A possible error
+   * @private
+   */
+  getPayloadLength64() {
+    if (this._bufferedBytes < 8) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(8);
+    const num = buf.readUInt32BE(0);
+
+    //
+    // The maximum safe integer in JavaScript is 2^53 - 1. An error is returned
+    // if payload length is greater than this number.
+    //
+    if (num > Math.pow(2, 53 - 32) - 1) {
+      this._loop = false;
+      return error(
+        RangeError,
+        'Unsupported WebSocket frame: payload length > 2^53 - 1',
+        false,
+        1009
+      );
+    }
+
+    this._payloadLength = num * Math.pow(2, 32) + buf.readUInt32BE(4);
+    return this.haveLength();
+  }
+
+  /**
+   * Payload length has been read.
+   *
+   * @return {(RangeError|undefined)} A possible error
+   * @private
+   */
+  haveLength() {
+    if (this._payloadLength && this._opcode < 0x08) {
+      this._totalPayloadLength += this._payloadLength;
+      if (this._totalPayloadLength > this._maxPayload && this._maxPayload > 0) {
+        this._loop = false;
+        return error(RangeError, 'Max payload size exceeded', false, 1009);
+      }
+    }
+
+    if (this._masked) this._state = GET_MASK;
+    else this._state = GET_DATA;
+  }
+
+  /**
+   * Reads mask bytes.
+   *
+   * @private
+   */
+  getMask() {
+    if (this._bufferedBytes < 4) {
+      this._loop = false;
+      return;
+    }
+
+    this._mask = this.consume(4);
+    this._state = GET_DATA;
+  }
+
+  /**
+   * Reads data bytes.
+   *
+   * @param {Function} cb Callback
+   * @return {(Error|RangeError|undefined)} A possible error
+   * @private
+   */
+  getData(cb) {
+    var data = EMPTY_BUFFER;
+
+    if (this._payloadLength) {
+      if (this._bufferedBytes < this._payloadLength) {
+        this._loop = false;
+        return;
+      }
+
+      data = this.consume(this._payloadLength);
+      if (this._masked) unmask(data, this._mask);
+    }
+
+    if (this._opcode > 0x07) return this.controlMessage(data);
+
+    if (this._compressed) {
+      this._state = INFLATING;
+      this.decompress(data, cb);
+      return;
+    }
+
+    if (data.length) {
+      //
+      // This message is not compressed so its lenght is the sum of the payload
+      // length of all fragments.
+      //
+      this._messageLength = this._totalPayloadLength;
+      this._fragments.push(data);
+    }
+
+    return this.dataMessage();
+  }
+
+  /**
+   * Decompresses data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Function} cb Callback
+   * @private
+   */
+  decompress(data, cb) {
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    perMessageDeflate.decompress(data, this._fin, (err, buf) => {
+      if (err) return cb(err);
+
+      if (buf.length) {
+        this._messageLength += buf.length;
+        if (this._messageLength > this._maxPayload && this._maxPayload > 0) {
+          return cb(
+            error(RangeError, 'Max payload size exceeded', false, 1009)
+          );
+        }
+
+        this._fragments.push(buf);
+      }
+
+      const er = this.dataMessage();
+      if (er) return cb(er);
+
+      this.startLoop(cb);
+    });
+  }
+
+  /**
+   * Handles a data message.
+   *
+   * @return {(Error|undefined)} A possible error
+   * @private
+   */
+  dataMessage() {
+    if (this._fin) {
+      const messageLength = this._messageLength;
+      const fragments = this._fragments;
+
+      this._totalPayloadLength = 0;
+      this._messageLength = 0;
+      this._fragmented = 0;
+      this._fragments = [];
+
+      if (this._opcode === 2) {
+        var data;
+
+        if (this._binaryType === 'nodebuffer') {
+          data = concat(fragments, messageLength);
+        } else if (this._binaryType === 'arraybuffer') {
+          data = toArrayBuffer(concat(fragments, messageLength));
+        } else {
+          data = fragments;
+        }
+
+        this.emit('message', data);
+      } else {
+        const buf = concat(fragments, messageLength);
+
+        if (!isValidUTF8(buf)) {
+          this._loop = false;
+          return error(Error, 'invalid UTF-8 sequence', true, 1007);
+        }
+
+        this.emit('message', buf.toString());
+      }
+    }
+
+    this._state = GET_INFO;
+  }
+
+  /**
+   * Handles a control message.
+   *
+   * @param {Buffer} data Data to handle
+   * @return {(Error|RangeError|undefined)} A possible error
+   * @private
+   */
+  controlMessage(data) {
+    if (this._opcode === 0x08) {
+      this._loop = false;
+
+      if (data.length === 0) {
+        this.emit('conclude', 1005, '');
+        this.end();
+      } else if (data.length === 1) {
+        return error(RangeError, 'invalid payload length 1', true, 1002);
+      } else {
+        const code = data.readUInt16BE(0);
+
+        if (!isValidStatusCode(code)) {
+          return error(RangeError, `invalid status code ${code}`, true, 1002);
+        }
+
+        const buf = data.slice(2);
+
+        if (!isValidUTF8(buf)) {
+          return error(Error, 'invalid UTF-8 sequence', true, 1007);
+        }
+
+        this.emit('conclude', code, buf.toString());
+        this.end();
+      }
+    } else if (this._opcode === 0x09) {
+      this.emit('ping', data);
+    } else {
+      this.emit('pong', data);
+    }
+
+    this._state = GET_INFO;
+  }
+}
+
+module.exports = Receiver;
+
+/**
+ * Builds an error object.
+ *
+ * @param {(Error|RangeError)} ErrorCtor The error constructor
+ * @param {String} message The error message
+ * @param {Boolean} prefix Specifies whether or not to add a default prefix to
+ *     `message`
+ * @param {Number} statusCode The status code
+ * @return {(Error|RangeError)} The error
+ * @private
+ */
+function error(ErrorCtor, message, prefix, statusCode) {
+  const err = new ErrorCtor(
+    prefix ? `Invalid WebSocket frame: ${message}` : message
+  );
+
+  Error.captureStackTrace(err, error);
+  err[kStatusCode] = statusCode;
+  return err;
+}

node_modules/y-websocket/node_modules/ws/lib/sender.js

@@ -0,0 +1,358 @@
+'use strict';
+
+const { randomBytes } = require('crypto');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const { EMPTY_BUFFER } = require('./constants');
+const { isValidStatusCode } = require('./validation');
+const { mask: applyMask, toBuffer } = require('./buffer-util');
+
+/**
+ * HyBi Sender implementation.
+ */
+class Sender {
+  /**
+   * Creates a Sender instance.
+   *
+   * @param {net.Socket} socket The connection socket
+   * @param {Object} extensions An object containing the negotiated extensions
+   */
+  constructor(socket, extensions) {
+    this._extensions = extensions || {};
+    this._socket = socket;
+
+    this._firstFragment = true;
+    this._compress = false;
+
+    this._bufferedBytes = 0;
+    this._deflating = false;
+    this._queue = [];
+  }
+
+  /**
+   * Frames a piece of data according to the HyBi WebSocket protocol.
+   *
+   * @param {Buffer} data The data to frame
+   * @param {Object} options Options object
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} options.readOnly Specifies whether `data` can be modified
+   * @param {Boolean} options.fin Specifies whether or not to set the FIN bit
+   * @param {Boolean} options.mask Specifies whether or not to mask `data`
+   * @param {Boolean} options.rsv1 Specifies whether or not to set the RSV1 bit
+   * @return {Buffer[]} The framed data as a list of `Buffer` instances
+   * @public
+   */
+  static frame(data, options) {
+    const merge = options.mask && options.readOnly;
+    var offset = options.mask ? 6 : 2;
+    var payloadLength = data.length;
+
+    if (data.length >= 65536) {
+      offset += 8;
+      payloadLength = 127;
+    } else if (data.length > 125) {
+      offset += 2;
+      payloadLength = 126;
+    }
+
+    const target = Buffer.allocUnsafe(merge ? data.length + offset : offset);
+
+    target[0] = options.fin ? options.opcode | 0x80 : options.opcode;
+    if (options.rsv1) target[0] |= 0x40;
+
+    target[1] = payloadLength;
+
+    if (payloadLength === 126) {
+      target.writeUInt16BE(data.length, 2);
+    } else if (payloadLength === 127) {
+      target.writeUInt32BE(0, 2);
+      target.writeUInt32BE(data.length, 6);
+    }
+
+    if (!options.mask) return [target, data];
+
+    const mask = randomBytes(4);
+
+    target[1] |= 0x80;
+    target[offset - 4] = mask[0];
+    target[offset - 3] = mask[1];
+    target[offset - 2] = mask[2];
+    target[offset - 1] = mask[3];
+
+    if (merge) {
+      applyMask(data, mask, target, offset, data.length);
+      return [target];
+    }
+
+    applyMask(data, mask, data, 0, data.length);
+    return [target, data];
+  }
+
+  /**
+   * Sends a close message to the other peer.
+   *
+   * @param {(Number|undefined)} code The status code component of the body
+   * @param {String} data The message component of the body
+   * @param {Boolean} mask Specifies whether or not to mask the message
+   * @param {Function} cb Callback
+   * @public
+   */
+  close(code, data, mask, cb) {
+    var buf;
+
+    if (code === undefined) {
+      buf = EMPTY_BUFFER;
+    } else if (typeof code !== 'number' || !isValidStatusCode(code)) {
+      throw new TypeError('First argument must be a valid error code number');
+    } else if (data === undefined || data === '') {
+      buf = Buffer.allocUnsafe(2);
+      buf.writeUInt16BE(code, 0);
+    } else {
+      buf = Buffer.allocUnsafe(2 + Buffer.byteLength(data));
+      buf.writeUInt16BE(code, 0);
+      buf.write(data, 2);
+    }
+
+    if (this._deflating) {
+      this.enqueue([this.doClose, buf, mask, cb]);
+    } else {
+      this.doClose(buf, mask, cb);
+    }
+  }
+
+  /**
+   * Frames and sends a close message.
+   *
+   * @param {Buffer} data The message to send
+   * @param {Boolean} mask Specifies whether or not to mask `data`
+   * @param {Function} cb Callback
+   * @private
+   */
+  doClose(data, mask, cb) {
+    this.sendFrame(
+      Sender.frame(data, {
+        fin: true,
+        rsv1: false,
+        opcode: 0x08,
+        mask,
+        readOnly: false
+      }),
+      cb
+    );
+  }
+
+  /**
+   * Sends a ping message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} mask Specifies whether or not to mask `data`
+   * @param {Function} cb Callback
+   * @public
+   */
+  ping(data, mask, cb) {
+    const buf = toBuffer(data);
+
+    if (this._deflating) {
+      this.enqueue([this.doPing, buf, mask, toBuffer.readOnly, cb]);
+    } else {
+      this.doPing(buf, mask, toBuffer.readOnly, cb);
+    }
+  }
+
+  /**
+   * Frames and sends a ping message.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} mask Specifies whether or not to mask `data`
+   * @param {Boolean} readOnly Specifies whether `data` can be modified
+   * @param {Function} cb Callback
+   * @private
+   */
+  doPing(data, mask, readOnly, cb) {
+    this.sendFrame(
+      Sender.frame(data, {
+        fin: true,
+        rsv1: false,
+        opcode: 0x09,
+        mask,
+        readOnly
+      }),
+      cb
+    );
+  }
+
+  /**
+   * Sends a pong message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} mask Specifies whether or not to mask `data`
+   * @param {Function} cb Callback
+   * @public
+   */
+  pong(data, mask, cb) {
+    const buf = toBuffer(data);
+
+    if (this._deflating) {
+      this.enqueue([this.doPong, buf, mask, toBuffer.readOnly, cb]);
+    } else {
+      this.doPong(buf, mask, toBuffer.readOnly, cb);
+    }
+  }
+
+  /**
+   * Frames and sends a pong message.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} mask Specifies whether or not to mask `data`
+   * @param {Boolean} readOnly Specifies whether `data` can be modified
+   * @param {Function} cb Callback
+   * @private
+   */
+  doPong(data, mask, readOnly, cb) {
+    this.sendFrame(
+      Sender.frame(data, {
+        fin: true,
+        rsv1: false,
+        opcode: 0x0a,
+        mask,
+        readOnly
+      }),
+      cb
+    );
+  }
+
+  /**
+   * Sends a data message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Object} options Options object
+   * @param {Boolean} options.compress Specifies whether or not to compress `data`
+   * @param {Boolean} options.binary Specifies whether `data` is binary or text
+   * @param {Boolean} options.fin Specifies whether the fragment is the last one
+   * @param {Boolean} options.mask Specifies whether or not to mask `data`
+   * @param {Function} cb Callback
+   * @public
+   */
+  send(data, options, cb) {
+    const buf = toBuffer(data);
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+    var opcode = options.binary ? 2 : 1;
+    var rsv1 = options.compress;
+
+    if (this._firstFragment) {
+      this._firstFragment = false;
+      if (rsv1 && perMessageDeflate) {
+        rsv1 = buf.length >= perMessageDeflate._threshold;
+      }
+      this._compress = rsv1;
+    } else {
+      rsv1 = false;
+      opcode = 0;
+    }
+
+    if (options.fin) this._firstFragment = true;
+
+    if (perMessageDeflate) {
+      const opts = {
+        fin: options.fin,
+        rsv1,
+        opcode,
+        mask: options.mask,
+        readOnly: toBuffer.readOnly
+      };
+
+      if (this._deflating) {
+        this.enqueue([this.dispatch, buf, this._compress, opts, cb]);
+      } else {
+        this.dispatch(buf, this._compress, opts, cb);
+      }
+    } else {
+      this.sendFrame(
+        Sender.frame(buf, {
+          fin: options.fin,
+          rsv1: false,
+          opcode,
+          mask: options.mask,
+          readOnly: toBuffer.readOnly
+        }),
+        cb
+      );
+    }
+  }
+
+  /**
+   * Dispatches a data message.
+   *
+   * @param {Buffer} data The message to send
+   * @param {Boolean} compress Specifies whether or not to compress `data`
+   * @param {Object} options Options object
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} options.readOnly Specifies whether `data` can be modified
+   * @param {Boolean} options.fin Specifies whether or not to set the FIN bit
+   * @param {Boolean} options.mask Specifies whether or not to mask `data`
+   * @param {Boolean} options.rsv1 Specifies whether or not to set the RSV1 bit
+   * @param {Function} cb Callback
+   * @private
+   */
+  dispatch(data, compress, options, cb) {
+    if (!compress) {
+      this.sendFrame(Sender.frame(data, options), cb);
+      return;
+    }
+
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    this._deflating = true;
+    perMessageDeflate.compress(data, options.fin, (_, buf) => {
+      this._deflating = false;
+      options.readOnly = false;
+      this.sendFrame(Sender.frame(buf, options), cb);
+      this.dequeue();
+    });
+  }
+
+  /**
+   * Executes queued send operations.
+   *
+   * @private
+   */
+  dequeue() {
+    while (!this._deflating && this._queue.length) {
+      const params = this._queue.shift();
+
+      this._bufferedBytes -= params[1].length;
+      params[0].apply(this, params.slice(1));
+    }
+  }
+
+  /**
+   * Enqueues a send operation.
+   *
+   * @param {Array} params Send operation parameters.
+   * @private
+   */
+  enqueue(params) {
+    this._bufferedBytes += params[1].length;
+    this._queue.push(params);
+  }
+
+  /**
+   * Sends a frame.
+   *
+   * @param {Buffer[]} list The frame to send
+   * @param {Function} cb Callback
+   * @private
+   */
+  sendFrame(list, cb) {
+    if (list.length === 2) {
+      this._socket.cork();
+      this._socket.write(list[0]);
+      this._socket.write(list[1], cb);
+      this._socket.uncork();
+    } else {
+      this._socket.write(list[0], cb);
+    }
+  }
+}
+
+module.exports = Sender;

node_modules/y-websocket/node_modules/ws/lib/validation.js

@@ -0,0 +1,30 @@
+'use strict';
+
+try {
+  const isValidUTF8 = require('utf-8-validate');
+
+  exports.isValidUTF8 =
+    typeof isValidUTF8 === 'object'
+      ? isValidUTF8.Validation.isValidUTF8 // utf-8-validate@<3.0.0
+      : isValidUTF8;
+} catch (e) /* istanbul ignore next */ {
+  exports.isValidUTF8 = () => true;
+}
+
+/**
+ * Checks if a status code is allowed in a close frame.
+ *
+ * @param {Number} code The status code
+ * @return {Boolean} `true` if the status code is valid, else `false`
+ * @public
+ */
+exports.isValidStatusCode = (code) => {
+  return (
+    (code >= 1000 &&
+      code <= 1013 &&
+      code !== 1004 &&
+      code !== 1005 &&
+      code !== 1006) ||
+    (code >= 3000 && code <= 4999)
+  );
+};

node_modules/y-websocket/node_modules/ws/lib/websocket-server.js

@@ -0,0 +1,415 @@
+'use strict';
+
+const EventEmitter = require('events');
+const crypto = require('crypto');
+const http = require('http');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const extension = require('./extension');
+const WebSocket = require('./websocket');
+const { GUID } = require('./constants');
+
+const keyRegex = /^[+/0-9A-Za-z]{22}==$/;
+
+/**
+ * Class representing a WebSocket server.
+ *
+ * @extends EventEmitter
+ */
+class WebSocketServer extends EventEmitter {
+  /**
+   * Create a `WebSocketServer` instance.
+   *
+   * @param {Object} options Configuration options
+   * @param {Number} options.backlog The maximum length of the queue of pending
+   *     connections
+   * @param {Boolean} options.clientTracking Specifies whether or not to track
+   *     clients
+   * @param {Function} options.handleProtocols An hook to handle protocols
+   * @param {String} options.host The hostname where to bind the server
+   * @param {Number} options.maxPayload The maximum allowed message size
+   * @param {Boolean} options.noServer Enable no server mode
+   * @param {String} options.path Accept only connections matching this path
+   * @param {(Boolean|Object)} options.perMessageDeflate Enable/disable
+   *     permessage-deflate
+   * @param {Number} options.port The port where to bind the server
+   * @param {http.Server} options.server A pre-created HTTP/S server to use
+   * @param {Function} options.verifyClient An hook to reject connections
+   * @param {Function} callback A listener for the `listening` event
+   */
+  constructor(options, callback) {
+    super();
+
+    options = Object.assign(
+      {
+        maxPayload: 100 * 1024 * 1024,
+        perMessageDeflate: false,
+        handleProtocols: null,
+        clientTracking: true,
+        verifyClient: null,
+        noServer: false,
+        backlog: null, // use default (511 as implemented in net.js)
+        server: null,
+        host: null,
+        path: null,
+        port: null
+      },
+      options
+    );
+
+    if (options.port == null && !options.server && !options.noServer) {
+      throw new TypeError(
+        'One of the "port", "server", or "noServer" options must be specified'
+      );
+    }
+
+    if (options.port != null) {
+      this._server = http.createServer((req, res) => {
+        const body = http.STATUS_CODES[426];
+
+        res.writeHead(426, {
+          'Content-Length': body.length,
+          'Content-Type': 'text/plain'
+        });
+        res.end(body);
+      });
+      this._server.listen(
+        options.port,
+        options.host,
+        options.backlog,
+        callback
+      );
+    } else if (options.server) {
+      this._server = options.server;
+    }
+
+    if (this._server) {
+      this._removeListeners = addListeners(this._server, {
+        listening: this.emit.bind(this, 'listening'),
+        error: this.emit.bind(this, 'error'),
+        upgrade: (req, socket, head) => {
+          this.handleUpgrade(req, socket, head, (ws) => {
+            this.emit('connection', ws, req);
+          });
+        }
+      });
+    }
+
+    if (options.perMessageDeflate === true) options.perMessageDeflate = {};
+    if (options.clientTracking) this.clients = new Set();
+    this.options = options;
+  }
+
+  /**
+   * Returns the bound address, the address family name, and port of the server
+   * as reported by the operating system if listening on an IP socket.
+   * If the server is listening on a pipe or UNIX domain socket, the name is
+   * returned as a string.
+   *
+   * @return {(Object|String|null)} The address of the server
+   * @public
+   */
+  address() {
+    if (this.options.noServer) {
+      throw new Error('The server is operating in "noServer" mode');
+    }
+
+    if (!this._server) return null;
+    return this._server.address();
+  }
+
+  /**
+   * Close the server.
+   *
+   * @param {Function} cb Callback
+   * @public
+   */
+  close(cb) {
+    if (cb) this.once('close', cb);
+
+    //
+    // Terminate all associated clients.
+    //
+    if (this.clients) {
+      for (const client of this.clients) client.terminate();
+    }
+
+    const server = this._server;
+
+    if (server) {
+      this._removeListeners();
+      this._removeListeners = this._server = null;
+
+      //
+      // Close the http server if it was internally created.
+      //
+      if (this.options.port != null) {
+        server.close(() => this.emit('close'));
+        return;
+      }
+    }
+
+    process.nextTick(emitClose, this);
+  }
+
+  /**
+   * See if a given request should be handled by this server instance.
+   *
+   * @param {http.IncomingMessage} req Request object to inspect
+   * @return {Boolean} `true` if the request is valid, else `false`
+   * @public
+   */
+  shouldHandle(req) {
+    if (this.options.path) {
+      const index = req.url.indexOf('?');
+      const pathname = index !== -1 ? req.url.slice(0, index) : req.url;
+
+      if (pathname !== this.options.path) return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Handle a HTTP Upgrade request.
+   *
+   * @param {http.IncomingMessage} req The request object
+   * @param {net.Socket} socket The network socket between the server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @public
+   */
+  handleUpgrade(req, socket, head, cb) {
+    socket.on('error', socketOnError);
+
+    const key =
+      req.headers['sec-websocket-key'] !== undefined
+        ? req.headers['sec-websocket-key'].trim()
+        : false;
+    const upgrade = req.headers.upgrade;
+    const version = +req.headers['sec-websocket-version'];
+    const extensions = {};
+
+    if (
+      req.method !== 'GET' ||
+      upgrade === undefined ||
+      upgrade.toLowerCase() !== 'websocket' ||
+      !key ||
+      !keyRegex.test(key) ||
+      (version !== 8 && version !== 13) ||
+      !this.shouldHandle(req)
+    ) {
+      return abortHandshake(socket, 400);
+    }
+
+    if (this.options.perMessageDeflate) {
+      const perMessageDeflate = new PerMessageDeflate(
+        this.options.perMessageDeflate,
+        true,
+        this.options.maxPayload
+      );
+
+      try {
+        const offers = extension.parse(req.headers['sec-websocket-extensions']);
+
+        if (offers[PerMessageDeflate.extensionName]) {
+          perMessageDeflate.accept(offers[PerMessageDeflate.extensionName]);
+          extensions[PerMessageDeflate.extensionName] = perMessageDeflate;
+        }
+      } catch (err) {
+        return abortHandshake(socket, 400);
+      }
+    }
+
+    //
+    // Optionally call external client verification handler.
+    //
+    if (this.options.verifyClient) {
+      const info = {
+        origin:
+          req.headers[`${version === 8 ? 'sec-websocket-origin' : 'origin'}`],
+        secure: !!(req.connection.authorized || req.connection.encrypted),
+        req
+      };
+
+      if (this.options.verifyClient.length === 2) {
+        this.options.verifyClient(info, (verified, code, message, headers) => {
+          if (!verified) {
+            return abortHandshake(socket, code || 401, message, headers);
+          }
+
+          this.completeUpgrade(key, extensions, req, socket, head, cb);
+        });
+        return;
+      }
+
+      if (!this.options.verifyClient(info)) return abortHandshake(socket, 401);
+    }
+
+    this.completeUpgrade(key, extensions, req, socket, head, cb);
+  }
+
+  /**
+   * Upgrade the connection to WebSocket.
+   *
+   * @param {String} key The value of the `Sec-WebSocket-Key` header
+   * @param {Object} extensions The accepted extensions
+   * @param {http.IncomingMessage} req The request object
+   * @param {net.Socket} socket The network socket between the server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @private
+   */
+  completeUpgrade(key, extensions, req, socket, head, cb) {
+    //
+    // Destroy the socket if the client has already sent a FIN packet.
+    //
+    if (!socket.readable || !socket.writable) return socket.destroy();
+
+    const digest = crypto
+      .createHash('sha1')
+      .update(key + GUID)
+      .digest('base64');
+
+    const headers = [
+      'HTTP/1.1 101 Switching Protocols',
+      'Upgrade: websocket',
+      'Connection: Upgrade',
+      `Sec-WebSocket-Accept: ${digest}`
+    ];
+
+    const ws = new WebSocket(null);
+    var protocol = req.headers['sec-websocket-protocol'];
+
+    if (protocol) {
+      protocol = protocol.split(',').map(trim);
+
+      //
+      // Optionally call external protocol selection handler.
+      //
+      if (this.options.handleProtocols) {
+        protocol = this.options.handleProtocols(protocol, req);
+      } else {
+        protocol = protocol[0];
+      }
+
+      if (protocol) {
+        headers.push(`Sec-WebSocket-Protocol: ${protocol}`);
+        ws.protocol = protocol;
+      }
+    }
+
+    if (extensions[PerMessageDeflate.extensionName]) {
+      const params = extensions[PerMessageDeflate.extensionName].params;
+      const value = extension.format({
+        [PerMessageDeflate.extensionName]: [params]
+      });
+      headers.push(`Sec-WebSocket-Extensions: ${value}`);
+      ws._extensions = extensions;
+    }
+
+    //
+    // Allow external modification/inspection of handshake headers.
+    //
+    this.emit('headers', headers, req);
+
+    socket.write(headers.concat('\r\n').join('\r\n'));
+    socket.removeListener('error', socketOnError);
+
+    ws.setSocket(socket, head, this.options.maxPayload);
+
+    if (this.clients) {
+      this.clients.add(ws);
+      ws.on('close', () => this.clients.delete(ws));
+    }
+
+    cb(ws);
+  }
+}
+
+module.exports = WebSocketServer;
+
+/**
+ * Add event listeners on an `EventEmitter` using a map of <event, listener>
+ * pairs.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @param {Object.<String, Function>} map The listeners to add
+ * @return {Function} A function that will remove the added listeners when called
+ * @private
+ */
+function addListeners(server, map) {
+  for (const event of Object.keys(map)) server.on(event, map[event]);
+
+  return function removeListeners() {
+    for (const event of Object.keys(map)) {
+      server.removeListener(event, map[event]);
+    }
+  };
+}
+
+/**
+ * Emit a `'close'` event on an `EventEmitter`.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @private
+ */
+function emitClose(server) {
+  server.emit('close');
+}
+
+/**
+ * Handle premature socket errors.
+ *
+ * @private
+ */
+function socketOnError() {
+  this.destroy();
+}
+
+/**
+ * Close the connection when preconditions are not fulfilled.
+ *
+ * @param {net.Socket} socket The socket of the upgrade request
+ * @param {Number} code The HTTP response status code
+ * @param {String} [message] The HTTP response body
+ * @param {Object} [headers] Additional HTTP response headers
+ * @private
+ */
+function abortHandshake(socket, code, message, headers) {
+  if (socket.writable) {
+    message = message || http.STATUS_CODES[code];
+    headers = Object.assign(
+      {
+        Connection: 'close',
+        'Content-type': 'text/html',
+        'Content-Length': Buffer.byteLength(message)
+      },
+      headers
+    );
+
+    socket.write(
+      `HTTP/1.1 ${code} ${http.STATUS_CODES[code]}\r\n` +
+        Object.keys(headers)
+          .map((h) => `${h}: ${headers[h]}`)
+          .join('\r\n') +
+        '\r\n\r\n' +
+        message
+    );
+  }
+
+  socket.removeListener('error', socketOnError);
+  socket.destroy();
+}
+
+/**
+ * Remove whitespace characters from both ends of a string.
+ *
+ * @param {String} str The string
+ * @return {String} A new string representing `str` stripped of whitespace
+ *     characters from both its beginning and end
+ * @private
+ */
+function trim(str) {
+  return str.trim();
+}

node_modules/y-websocket/node_modules/ws/lib/websocket.js

@@ -0,0 +1,895 @@
+'use strict';
+
+const EventEmitter = require('events');
+const crypto = require('crypto');
+const https = require('https');
+const http = require('http');
+const net = require('net');
+const tls = require('tls');
+const url = require('url');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const EventTarget = require('./event-target');
+const extension = require('./extension');
+const Receiver = require('./receiver');
+const Sender = require('./sender');
+const {
+  BINARY_TYPES,
+  EMPTY_BUFFER,
+  GUID,
+  kStatusCode,
+  kWebSocket,
+  NOOP
+} = require('./constants');
+
+const readyStates = ['CONNECTING', 'OPEN', 'CLOSING', 'CLOSED'];
+const protocolVersions = [8, 13];
+const closeTimeout = 30 * 1000;
+
+/**
+ * Class representing a WebSocket.
+ *
+ * @extends EventEmitter
+ */
+class WebSocket extends EventEmitter {
+  /**
+   * Create a new `WebSocket`.
+   *
+   * @param {(String|url.Url|url.URL)} address The URL to which to connect
+   * @param {(String|String[])} protocols The subprotocols
+   * @param {Object} options Connection options
+   */
+  constructor(address, protocols, options) {
+    super();
+
+    this.readyState = WebSocket.CONNECTING;
+    this.protocol = '';
+
+    this._binaryType = BINARY_TYPES[0];
+    this._closeFrameReceived = false;
+    this._closeFrameSent = false;
+    this._closeMessage = '';
+    this._closeTimer = null;
+    this._closeCode = 1006;
+    this._extensions = {};
+    this._receiver = null;
+    this._sender = null;
+    this._socket = null;
+
+    if (address !== null) {
+      this._isServer = false;
+      this._redirects = 0;
+
+      if (Array.isArray(protocols)) {
+        protocols = protocols.join(', ');
+      } else if (typeof protocols === 'object' && protocols !== null) {
+        options = protocols;
+        protocols = undefined;
+      }
+
+      initAsClient(this, address, protocols, options);
+    } else {
+      this._isServer = true;
+    }
+  }
+
+  get CONNECTING() {
+    return WebSocket.CONNECTING;
+  }
+  get CLOSING() {
+    return WebSocket.CLOSING;
+  }
+  get CLOSED() {
+    return WebSocket.CLOSED;
+  }
+  get OPEN() {
+    return WebSocket.OPEN;
+  }
+
+  /**
+   * This deviates from the WHATWG interface since ws doesn't support the
+   * required default "blob" type (instead we define a custom "nodebuffer"
+   * type).
+   *
+   * @type {String}
+   */
+  get binaryType() {
+    return this._binaryType;
+  }
+
+  set binaryType(type) {
+    if (!BINARY_TYPES.includes(type)) return;
+
+    this._binaryType = type;
+
+    //
+    // Allow to change `binaryType` on the fly.
+    //
+    if (this._receiver) this._receiver._binaryType = type;
+  }
+
+  /**
+   * @type {Number}
+   */
+  get bufferedAmount() {
+    if (!this._socket) return 0;
+
+    //
+    // `socket.bufferSize` is `undefined` if the socket is closed.
+    //
+    return (this._socket.bufferSize || 0) + this._sender._bufferedBytes;
+  }
+
+  /**
+   * @type {String}
+   */
+  get extensions() {
+    return Object.keys(this._extensions).join();
+  }
+
+  /**
+   * Set up the socket and the internal resources.
+   *
+   * @param {net.Socket} socket The network socket between the server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Number} maxPayload The maximum allowed message size
+   * @private
+   */
+  setSocket(socket, head, maxPayload) {
+    const receiver = new Receiver(
+      this._binaryType,
+      this._extensions,
+      maxPayload
+    );
+
+    this._sender = new Sender(socket, this._extensions);
+    this._receiver = receiver;
+    this._socket = socket;
+
+    receiver[kWebSocket] = this;
+    socket[kWebSocket] = this;
+
+    receiver.on('conclude', receiverOnConclude);
+    receiver.on('drain', receiverOnDrain);
+    receiver.on('error', receiverOnError);
+    receiver.on('message', receiverOnMessage);
+    receiver.on('ping', receiverOnPing);
+    receiver.on('pong', receiverOnPong);
+
+    socket.setTimeout(0);
+    socket.setNoDelay();
+
+    if (head.length > 0) socket.unshift(head);
+
+    socket.on('close', socketOnClose);
+    socket.on('data', socketOnData);
+    socket.on('end', socketOnEnd);
+    socket.on('error', socketOnError);
+
+    this.readyState = WebSocket.OPEN;
+    this.emit('open');
+  }
+
+  /**
+   * Emit the `'close'` event.
+   *
+   * @private
+   */
+  emitClose() {
+    this.readyState = WebSocket.CLOSED;
+
+    if (!this._socket) {
+      this.emit('close', this._closeCode, this._closeMessage);
+      return;
+    }
+
+    if (this._extensions[PerMessageDeflate.extensionName]) {
+      this._extensions[PerMessageDeflate.extensionName].cleanup();
+    }
+
+    this._receiver.removeAllListeners();
+    this.emit('close', this._closeCode, this._closeMessage);
+  }
+
+  /**
+   * Start a closing handshake.
+   *
+   *          +----------+   +-----------+   +----------+
+   *     - - -|ws.close()|-->|close frame|-->|ws.close()|- - -
+   *    |     +----------+   +-----------+   +----------+     |
+   *          +----------+   +-----------+         |
+   * CLOSING  |ws.close()|<--|close frame|<--+-----+       CLOSING
+   *          +----------+   +-----------+   |
+   *    |           |                        |   +---+        |
+   *                +------------------------+-->|fin| - - - -
+   *    |         +---+                      |   +---+
+   *     - - - - -|fin|<---------------------+
+   *              +---+
+   *
+   * @param {Number} code Status code explaining why the connection is closing
+   * @param {String} data A string explaining why the connection is closing
+   * @public
+   */
+  close(code, data) {
+    if (this.readyState === WebSocket.CLOSED) return;
+    if (this.readyState === WebSocket.CONNECTING) {
+      const msg = 'WebSocket was closed before the connection was established';
+      return abortHandshake(this, this._req, msg);
+    }
+
+    if (this.readyState === WebSocket.CLOSING) {
+      if (this._closeFrameSent && this._closeFrameReceived) this._socket.end();
+      return;
+    }
+
+    this.readyState = WebSocket.CLOSING;
+    this._sender.close(code, data, !this._isServer, (err) => {
+      //
+      // This error is handled by the `'error'` listener on the socket. We only
+      // want to know if the close frame has been sent here.
+      //
+      if (err) return;
+
+      this._closeFrameSent = true;
+      if (this._closeFrameReceived) this._socket.end();
+    });
+
+    //
+    // Specify a timeout for the closing handshake to complete.
+    //
+    this._closeTimer = setTimeout(
+      this._socket.destroy.bind(this._socket),
+      closeTimeout
+    );
+  }
+
+  /**
+   * Send a ping.
+   *
+   * @param {*} data The data to send
+   * @param {Boolean} mask Indicates whether or not to mask `data`
+   * @param {Function} cb Callback which is executed when the ping is sent
+   * @public
+   */
+  ping(data, mask, cb) {
+    if (typeof data === 'function') {
+      cb = data;
+      data = mask = undefined;
+    } else if (typeof mask === 'function') {
+      cb = mask;
+      mask = undefined;
+    }
+
+    if (this.readyState !== WebSocket.OPEN) {
+      const err = new Error(
+        `WebSocket is not open: readyState ${this.readyState} ` +
+          `(${readyStates[this.readyState]})`
+      );
+
+      if (cb) return cb(err);
+      throw err;
+    }
+
+    if (typeof data === 'number') data = data.toString();
+    if (mask === undefined) mask = !this._isServer;
+    this._sender.ping(data || EMPTY_BUFFER, mask, cb);
+  }
+
+  /**
+   * Send a pong.
+   *
+   * @param {*} data The data to send
+   * @param {Boolean} mask Indicates whether or not to mask `data`
+   * @param {Function} cb Callback which is executed when the pong is sent
+   * @public
+   */
+  pong(data, mask, cb) {
+    if (typeof data === 'function') {
+      cb = data;
+      data = mask = undefined;
+    } else if (typeof mask === 'function') {
+      cb = mask;
+      mask = undefined;
+    }
+
+    if (this.readyState !== WebSocket.OPEN) {
+      const err = new Error(
+        `WebSocket is not open: readyState ${this.readyState} ` +
+          `(${readyStates[this.readyState]})`
+      );
+
+      if (cb) return cb(err);
+      throw err;
+    }
+
+    if (typeof data === 'number') data = data.toString();
+    if (mask === undefined) mask = !this._isServer;
+    this._sender.pong(data || EMPTY_BUFFER, mask, cb);
+  }
+
+  /**
+   * Send a data message.
+   *
+   * @param {*} data The message to send
+   * @param {Object} options Options object
+   * @param {Boolean} options.compress Specifies whether or not to compress `data`
+   * @param {Boolean} options.binary Specifies whether `data` is binary or text
+   * @param {Boolean} options.fin Specifies whether the fragment is the last one
+   * @param {Boolean} options.mask Specifies whether or not to mask `data`
+   * @param {Function} cb Callback which is executed when data is written out
+   * @public
+   */
+  send(data, options, cb) {
+    if (typeof options === 'function') {
+      cb = options;
+      options = {};
+    }
+
+    if (this.readyState !== WebSocket.OPEN) {
+      const err = new Error(
+        `WebSocket is not open: readyState ${this.readyState} ` +
+          `(${readyStates[this.readyState]})`
+      );
+
+      if (cb) return cb(err);
+      throw err;
+    }
+
+    if (typeof data === 'number') data = data.toString();
+
+    const opts = Object.assign(
+      {
+        binary: typeof data !== 'string',
+        mask: !this._isServer,
+        compress: true,
+        fin: true
+      },
+      options
+    );
+
+    if (!this._extensions[PerMessageDeflate.extensionName]) {
+      opts.compress = false;
+    }
+
+    this._sender.send(data || EMPTY_BUFFER, opts, cb);
+  }
+
+  /**
+   * Forcibly close the connection.
+   *
+   * @public
+   */
+  terminate() {
+    if (this.readyState === WebSocket.CLOSED) return;
+    if (this.readyState === WebSocket.CONNECTING) {
+      const msg = 'WebSocket was closed before the connection was established';
+      return abortHandshake(this, this._req, msg);
+    }
+
+    if (this._socket) {
+      this.readyState = WebSocket.CLOSING;
+      this._socket.destroy();
+    }
+  }
+}
+
+readyStates.forEach((readyState, i) => {
+  WebSocket[readyState] = i;
+});
+
+//
+// Add the `onopen`, `onerror`, `onclose`, and `onmessage` attributes.
+// See https://html.spec.whatwg.org/multipage/comms.html#the-websocket-interface
+//
+['open', 'error', 'close', 'message'].forEach((method) => {
+  Object.defineProperty(WebSocket.prototype, `on${method}`, {
+    /**
+     * Return the listener of the event.
+     *
+     * @return {(Function|undefined)} The event listener or `undefined`
+     * @public
+     */
+    get() {
+      const listeners = this.listeners(method);
+      for (var i = 0; i < listeners.length; i++) {
+        if (listeners[i]._listener) return listeners[i]._listener;
+      }
+
+      return undefined;
+    },
+    /**
+     * Add a listener for the event.
+     *
+     * @param {Function} listener The listener to add
+     * @public
+     */
+    set(listener) {
+      const listeners = this.listeners(method);
+      for (var i = 0; i < listeners.length; i++) {
+        //
+        // Remove only the listeners added via `addEventListener`.
+        //
+        if (listeners[i]._listener) this.removeListener(method, listeners[i]);
+      }
+      this.addEventListener(method, listener);
+    }
+  });
+});
+
+WebSocket.prototype.addEventListener = EventTarget.addEventListener;
+WebSocket.prototype.removeEventListener = EventTarget.removeEventListener;
+
+module.exports = WebSocket;
+
+/**
+ * Initialize a WebSocket client.
+ *
+ * @param {WebSocket} websocket The client to initialize
+ * @param {(String|url.Url|url.URL)} address The URL to which to connect
+ * @param {String} protocols The subprotocols
+ * @param {Object} options Connection options
+ * @param {(Boolean|Object)} options.perMessageDeflate Enable/disable
+ *     permessage-deflate
+ * @param {Number} options.handshakeTimeout Timeout in milliseconds for the
+ *     handshake request
+ * @param {Number} options.protocolVersion Value of the `Sec-WebSocket-Version`
+ *     header
+ * @param {String} options.origin Value of the `Origin` or
+ *     `Sec-WebSocket-Origin` header
+ * @param {Number} options.maxPayload The maximum allowed message size
+ * @param {Boolean} options.followRedirects Whether or not to follow redirects
+ * @param {Number} options.maxRedirects The maximum number of redirects allowed
+ * @private
+ */
+function initAsClient(websocket, address, protocols, options) {
+  const opts = Object.assign(
+    {
+      protocolVersion: protocolVersions[1],
+      maxPayload: 100 * 1024 * 1024,
+      perMessageDeflate: true,
+      followRedirects: false,
+      maxRedirects: 10
+    },
+    options,
+    {
+      createConnection: undefined,
+      socketPath: undefined,
+      hostname: undefined,
+      protocol: undefined,
+      timeout: undefined,
+      method: undefined,
+      auth: undefined,
+      host: undefined,
+      path: undefined,
+      port: undefined
+    }
+  );
+
+  if (!protocolVersions.includes(opts.protocolVersion)) {
+    throw new RangeError(
+      `Unsupported protocol version: ${opts.protocolVersion} ` +
+        `(supported versions: ${protocolVersions.join(', ')})`
+    );
+  }
+
+  var parsedUrl;
+
+  if (typeof address === 'object' && address.href !== undefined) {
+    parsedUrl = address;
+    websocket.url = address.href;
+  } else {
+    //
+    // The WHATWG URL constructor is not available on Node.js < 6.13.0
+    //
+    parsedUrl = url.URL ? new url.URL(address) : url.parse(address);
+    websocket.url = address;
+  }
+
+  const isUnixSocket = parsedUrl.protocol === 'ws+unix:';
+
+  if (!parsedUrl.host && (!isUnixSocket || !parsedUrl.pathname)) {
+    throw new Error(`Invalid URL: ${websocket.url}`);
+  }
+
+  const isSecure =
+    parsedUrl.protocol === 'wss:' || parsedUrl.protocol === 'https:';
+  const defaultPort = isSecure ? 443 : 80;
+  const key = crypto.randomBytes(16).toString('base64');
+  const get = isSecure ? https.get : http.get;
+  const path = parsedUrl.search
+    ? `${parsedUrl.pathname || '/'}${parsedUrl.search}`
+    : parsedUrl.pathname || '/';
+  var perMessageDeflate;
+
+  opts.createConnection = isSecure ? tlsConnect : netConnect;
+  opts.defaultPort = opts.defaultPort || defaultPort;
+  opts.port = parsedUrl.port || defaultPort;
+  opts.host = parsedUrl.hostname.startsWith('[')
+    ? parsedUrl.hostname.slice(1, -1)
+    : parsedUrl.hostname;
+  opts.headers = Object.assign(
+    {
+      'Sec-WebSocket-Version': opts.protocolVersion,
+      'Sec-WebSocket-Key': key,
+      Connection: 'Upgrade',
+      Upgrade: 'websocket'
+    },
+    opts.headers
+  );
+  opts.path = path;
+  opts.timeout = opts.handshakeTimeout;
+
+  if (opts.perMessageDeflate) {
+    perMessageDeflate = new PerMessageDeflate(
+      opts.perMessageDeflate !== true ? opts.perMessageDeflate : {},
+      false,
+      opts.maxPayload
+    );
+    opts.headers['Sec-WebSocket-Extensions'] = extension.format({
+      [PerMessageDeflate.extensionName]: perMessageDeflate.offer()
+    });
+  }
+  if (protocols) {
+    opts.headers['Sec-WebSocket-Protocol'] = protocols;
+  }
+  if (opts.origin) {
+    if (opts.protocolVersion < 13) {
+      opts.headers['Sec-WebSocket-Origin'] = opts.origin;
+    } else {
+      opts.headers.Origin = opts.origin;
+    }
+  }
+  if (parsedUrl.auth) {
+    opts.auth = parsedUrl.auth;
+  } else if (parsedUrl.username || parsedUrl.password) {
+    opts.auth = `${parsedUrl.username}:${parsedUrl.password}`;
+  }
+
+  if (isUnixSocket) {
+    const parts = path.split(':');
+
+    opts.socketPath = parts[0];
+    opts.path = parts[1];
+  }
+
+  var req = (websocket._req = get(opts));
+
+  if (opts.timeout) {
+    req.on('timeout', () => {
+      abortHandshake(websocket, req, 'Opening handshake has timed out');
+    });
+  }
+
+  req.on('error', (err) => {
+    if (websocket._req.aborted) return;
+
+    req = websocket._req = null;
+    websocket.readyState = WebSocket.CLOSING;
+    websocket.emit('error', err);
+    websocket.emitClose();
+  });
+
+  req.on('response', (res) => {
+    const location = res.headers.location;
+    const statusCode = res.statusCode;
+
+    if (
+      location &&
+      opts.followRedirects &&
+      statusCode >= 300 &&
+      statusCode < 400
+    ) {
+      if (++websocket._redirects > opts.maxRedirects) {
+        abortHandshake(websocket, req, 'Maximum redirects exceeded');
+        return;
+      }
+
+      req.abort();
+
+      const addr = url.URL
+        ? new url.URL(location, address)
+        : url.resolve(address, location);
+
+      initAsClient(websocket, addr, protocols, options);
+    } else if (!websocket.emit('unexpected-response', req, res)) {
+      abortHandshake(
+        websocket,
+        req,
+        `Unexpected server response: ${res.statusCode}`
+      );
+    }
+  });
+
+  req.on('upgrade', (res, socket, head) => {
+    websocket.emit('upgrade', res);
+
+    //
+    // The user may have closed the connection from a listener of the `upgrade`
+    // event.
+    //
+    if (websocket.readyState !== WebSocket.CONNECTING) return;
+
+    req = websocket._req = null;
+
+    const digest = crypto
+      .createHash('sha1')
+      .update(key + GUID)
+      .digest('base64');
+
+    if (res.headers['sec-websocket-accept'] !== digest) {
+      abortHandshake(websocket, socket, 'Invalid Sec-WebSocket-Accept header');
+      return;
+    }
+
+    const serverProt = res.headers['sec-websocket-protocol'];
+    const protList = (protocols || '').split(/, */);
+    var protError;
+
+    if (!protocols && serverProt) {
+      protError = 'Server sent a subprotocol but none was requested';
+    } else if (protocols && !serverProt) {
+      protError = 'Server sent no subprotocol';
+    } else if (serverProt && !protList.includes(serverProt)) {
+      protError = 'Server sent an invalid subprotocol';
+    }
+
+    if (protError) {
+      abortHandshake(websocket, socket, protError);
+      return;
+    }
+
+    if (serverProt) websocket.protocol = serverProt;
+
+    if (perMessageDeflate) {
+      try {
+        const extensions = extension.parse(
+          res.headers['sec-websocket-extensions']
+        );
+
+        if (extensions[PerMessageDeflate.extensionName]) {
+          perMessageDeflate.accept(extensions[PerMessageDeflate.extensionName]);
+          websocket._extensions[
+            PerMessageDeflate.extensionName
+          ] = perMessageDeflate;
+        }
+      } catch (err) {
+        abortHandshake(
+          websocket,
+          socket,
+          'Invalid Sec-WebSocket-Extensions header'
+        );
+        return;
+      }
+    }
+
+    websocket.setSocket(socket, head, opts.maxPayload);
+  });
+}
+
+/**
+ * Create a `net.Socket` and initiate a connection.
+ *
+ * @param {Object} options Connection options
+ * @return {net.Socket} The newly created socket used to start the connection
+ * @private
+ */
+function netConnect(options) {
+  //
+  // Override `options.path` only if `options` is a copy of the original options
+  // object. This is always true on Node.js >= 8 but not on Node.js 6 where
+  // `options.socketPath` might be `undefined` even if the `socketPath` option
+  // was originally set.
+  //
+  if (options.protocolVersion) options.path = options.socketPath;
+  return net.connect(options);
+}
+
+/**
+ * Create a `tls.TLSSocket` and initiate a connection.
+ *
+ * @param {Object} options Connection options
+ * @return {tls.TLSSocket} The newly created socket used to start the connection
+ * @private
+ */
+function tlsConnect(options) {
+  options.path = undefined;
+  options.servername = options.servername || options.host;
+  return tls.connect(options);
+}
+
+/**
+ * Abort the handshake and emit an error.
+ *
+ * @param {WebSocket} websocket The WebSocket instance
+ * @param {(http.ClientRequest|net.Socket)} stream The request to abort or the
+ *     socket to destroy
+ * @param {String} message The error message
+ * @private
+ */
+function abortHandshake(websocket, stream, message) {
+  websocket.readyState = WebSocket.CLOSING;
+
+  const err = new Error(message);
+  Error.captureStackTrace(err, abortHandshake);
+
+  if (stream.setHeader) {
+    stream.abort();
+    stream.once('abort', websocket.emitClose.bind(websocket));
+    websocket.emit('error', err);
+  } else {
+    stream.destroy(err);
+    stream.once('error', websocket.emit.bind(websocket, 'error'));
+    stream.once('close', websocket.emitClose.bind(websocket));
+  }
+}
+
+/**
+ * The listener of the `Receiver` `'conclude'` event.
+ *
+ * @param {Number} code The status code
+ * @param {String} reason The reason for closing
+ * @private
+ */
+function receiverOnConclude(code, reason) {
+  const websocket = this[kWebSocket];
+
+  websocket._socket.removeListener('data', socketOnData);
+  websocket._socket.resume();
+
+  websocket._closeFrameReceived = true;
+  websocket._closeMessage = reason;
+  websocket._closeCode = code;
+
+  if (code === 1005) websocket.close();
+  else websocket.close(code, reason);
+}
+
+/**
+ * The listener of the `Receiver` `'drain'` event.
+ *
+ * @private
+ */
+function receiverOnDrain() {
+  this[kWebSocket]._socket.resume();
+}
+
+/**
+ * The listener of the `Receiver` `'error'` event.
+ *
+ * @param {(RangeError|Error)} err The emitted error
+ * @private
+ */
+function receiverOnError(err) {
+  const websocket = this[kWebSocket];
+
+  websocket._socket.removeListener('data', socketOnData);
+
+  websocket.readyState = WebSocket.CLOSING;
+  websocket._closeCode = err[kStatusCode];
+  websocket.emit('error', err);
+  websocket._socket.destroy();
+}
+
+/**
+ * The listener of the `Receiver` `'finish'` event.
+ *
+ * @private
+ */
+function receiverOnFinish() {
+  this[kWebSocket].emitClose();
+}
+
+/**
+ * The listener of the `Receiver` `'message'` event.
+ *
+ * @param {(String|Buffer|ArrayBuffer|Buffer[])} data The message
+ * @private
+ */
+function receiverOnMessage(data) {
+  this[kWebSocket].emit('message', data);
+}
+
+/**
+ * The listener of the `Receiver` `'ping'` event.
+ *
+ * @param {Buffer} data The data included in the ping frame
+ * @private
+ */
+function receiverOnPing(data) {
+  const websocket = this[kWebSocket];
+
+  websocket.pong(data, !websocket._isServer, NOOP);
+  websocket.emit('ping', data);
+}
+
+/**
+ * The listener of the `Receiver` `'pong'` event.
+ *
+ * @param {Buffer} data The data included in the pong frame
+ * @private
+ */
+function receiverOnPong(data) {
+  this[kWebSocket].emit('pong', data);
+}
+
+/**
+ * The listener of the `net.Socket` `'close'` event.
+ *
+ * @private
+ */
+function socketOnClose() {
+  const websocket = this[kWebSocket];
+
+  this.removeListener('close', socketOnClose);
+  this.removeListener('end', socketOnEnd);
+
+  websocket.readyState = WebSocket.CLOSING;
+
+  //
+  // The close frame might not have been received or the `'end'` event emitted,
+  // for example, if the socket was destroyed due to an error. Ensure that the
+  // `receiver` stream is closed after writing any remaining buffered data to
+  // it. If the readable side of the socket is in flowing mode then there is no
+  // buffered data as everything has been already written and `readable.read()`
+  // will return `null`. If instead, the socket is paused, any possible buffered
+  // data will be read as a single chunk and emitted synchronously in a single
+  // `'data'` event.
+  //
+  websocket._socket.read();
+  websocket._receiver.end();
+
+  this.removeListener('data', socketOnData);
+  this[kWebSocket] = undefined;
+
+  clearTimeout(websocket._closeTimer);
+
+  if (
+    websocket._receiver._writableState.finished ||
+    websocket._receiver._writableState.errorEmitted
+  ) {
+    websocket.emitClose();
+  } else {
+    websocket._receiver.on('error', receiverOnFinish);
+    websocket._receiver.on('finish', receiverOnFinish);
+  }
+}
+
+/**
+ * The listener of the `net.Socket` `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function socketOnData(chunk) {
+  if (!this[kWebSocket]._receiver.write(chunk)) {
+    this.pause();
+  }
+}
+
+/**
+ * The listener of the `net.Socket` `'end'` event.
+ *
+ * @private
+ */
+function socketOnEnd() {
+  const websocket = this[kWebSocket];
+
+  websocket.readyState = WebSocket.CLOSING;
+  websocket._receiver.end();
+  this.end();
+}
+
+/**
+ * The listener of the `net.Socket` `'error'` event.
+ *
+ * @private
+ */
+function socketOnError() {
+  const websocket = this[kWebSocket];
+
+  this.removeListener('error', socketOnError);
+  this.on('error', NOOP);
+
+  websocket.readyState = WebSocket.CLOSING;
+  this.destroy();
+}

node_modules/y-websocket/node_modules/ws/package.json

@@ -0,0 +1,45 @@
+{
+  "name": "ws",
+  "version": "6.2.3",
+  "description": "Simple to use, blazing fast and thoroughly tested websocket client and server for Node.js",
+  "keywords": [
+    "HyBi",
+    "Push",
+    "RFC-6455",
+    "WebSocket",
+    "WebSockets",
+    "real-time"
+  ],
+  "homepage": "https://github.com/websockets/ws",
+  "bugs": "https://github.com/websockets/ws/issues",
+  "repository": "websockets/ws",
+  "author": "Einar Otto Stangvik <einaros@gmail.com> (http://2x.io)",
+  "license": "MIT",
+  "main": "index.js",
+  "browser": "browser.js",
+  "files": [
+    "browser.js",
+    "index.js",
+    "lib/*.js"
+  ],
+  "scripts": {
+    "test": "npm run lint && nyc --reporter=html --reporter=text mocha test/*.test.js",
+    "integration": "npm run lint && mocha test/*.integration.js",
+    "lint": "eslint --ignore-path .gitignore . && prettier --check --ignore-path .gitignore \"**/*.{json,md,yml}\""
+  },
+  "dependencies": {
+    "async-limiter": "~1.0.0"
+  },
+  "devDependencies": {
+    "benchmark": "~2.1.4",
+    "bufferutil": "~4.0.0",
+    "coveralls": "~3.0.3",
+    "eslint": "~5.15.0",
+    "eslint-config-prettier": "~4.1.0",
+    "eslint-plugin-prettier": "~3.0.0",
+    "mocha": "~6.0.0",
+    "nyc": "~13.3.0",
+    "prettier": "~1.16.1",
+    "utf-8-validate": "~5.0.0"
+  }
+}

node_modules/y-websocket/package.json

@@ -0,0 +1,82 @@
+{
+  "name": "y-websocket",
+  "version": "1.5.4",
+  "description": "Websockets provider for Yjs",
+  "main": "./dist/y-websocket.cjs",
+  "module": "./src/y-websocket.js",
+  "types": "./dist/src/y-websocket.d.ts",
+  "sideEffects": false,
+  "funding": {
+    "type": "GitHub Sponsors ❤",
+    "url": "https://github.com/sponsors/dmonad"
+  },
+  "scripts": {
+    "start": "node ./bin/server.js",
+    "dist": "rm -rf dist && rollup -c && tsc",
+    "lint": "standard && tsc",
+    "test": "npm run lint",
+    "preversion": "npm run lint && npm run dist && test -e dist/src/y-websocket.d.ts && test -e dist/y-websocket.cjs"
+  },
+  "bin": {
+    "y-websocket-server": "./bin/server.js",
+    "y-websocket": "./bin/server.js"
+  },
+  "files": [
+    "dist/*",
+    "bin/*",
+    "src/*"
+  ],
+  "exports": {
+    "./package.json": "./package.json",
+    "./bin/utils": "./bin/utils.js",
+    "./bin/callback": "./bin/callback.js",
+    ".": {
+      "module": "./src/y-websocket.js",
+      "import": "./src/y-websocket.js",
+      "require": "./dist/y-websocket.cjs",
+      "types": "./dist/src/y-websocket.d.ts"
+    }
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/yjs/y-websocket.git"
+  },
+  "keywords": [
+    "Yjs"
+  ],
+  "author": "Kevin Jahns <kevin.jahns@protonmail.com>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/yjs/y-websocket/issues"
+  },
+  "homepage": "https://github.com/yjs/y-websocket#readme",
+  "standard": {
+    "ignore": [
+      "/dist",
+      "/node_modules"
+    ]
+  },
+  "dependencies": {
+    "lib0": "^0.2.52",
+    "lodash.debounce": "^4.0.8",
+    "y-protocols": "^1.0.5"
+  },
+  "devDependencies": {
+    "@types/node": "^18.15.0",
+    "rollup": "^3.19.1",
+    "standard": "^12.0.1",
+    "typescript": "^4.9.5",
+    "yjs": "^13.5.0"
+  },
+  "peerDependencies": {
+    "yjs": "^13.5.6"
+  },
+  "optionalDependencies": {
+    "ws": "^6.2.1",
+    "y-leveldb": "^0.1.0"
+  },
+  "engines": {
+    "npm": ">=8.0.0",
+    "node": ">=16.0.0"
+  }
+}

node_modules/y-websocket/src/y-websocket.js

@@ -0,0 +1,485 @@
+/**
+ * @module provider/websocket
+ */
+
+/* eslint-env browser */
+
+import * as Y from 'yjs' // eslint-disable-line
+import * as bc from 'lib0/broadcastchannel'
+import * as time from 'lib0/time'
+import * as encoding from 'lib0/encoding'
+import * as decoding from 'lib0/decoding'
+import * as syncProtocol from 'y-protocols/sync'
+import * as authProtocol from 'y-protocols/auth'
+import * as awarenessProtocol from 'y-protocols/awareness'
+import { Observable } from 'lib0/observable'
+import * as math from 'lib0/math'
+import * as url from 'lib0/url'
+import * as env from 'lib0/environment'
+
+export const messageSync = 0
+export const messageQueryAwareness = 3
+export const messageAwareness = 1
+export const messageAuth = 2
+
+/**
+ *                       encoder,          decoder,          provider,          emitSynced, messageType
+ * @type {Array<function(encoding.Encoder, decoding.Decoder, WebsocketProvider, boolean,    number):void>}
+ */
+const messageHandlers = []
+
+messageHandlers[messageSync] = (
+  encoder,
+  decoder,
+  provider,
+  emitSynced,
+  _messageType
+) => {
+  encoding.writeVarUint(encoder, messageSync)
+  const syncMessageType = syncProtocol.readSyncMessage(
+    decoder,
+    encoder,
+    provider.doc,
+    provider
+  )
+  if (
+    emitSynced && syncMessageType === syncProtocol.messageYjsSyncStep2 &&
+    !provider.synced
+  ) {
+    provider.synced = true
+  }
+}
+
+messageHandlers[messageQueryAwareness] = (
+  encoder,
+  _decoder,
+  provider,
+  _emitSynced,
+  _messageType
+) => {
+  encoding.writeVarUint(encoder, messageAwareness)
+  encoding.writeVarUint8Array(
+    encoder,
+    awarenessProtocol.encodeAwarenessUpdate(
+      provider.awareness,
+      Array.from(provider.awareness.getStates().keys())
+    )
+  )
+}
+
+messageHandlers[messageAwareness] = (
+  _encoder,
+  decoder,
+  provider,
+  _emitSynced,
+  _messageType
+) => {
+  awarenessProtocol.applyAwarenessUpdate(
+    provider.awareness,
+    decoding.readVarUint8Array(decoder),
+    provider
+  )
+}
+
+messageHandlers[messageAuth] = (
+  _encoder,
+  decoder,
+  provider,
+  _emitSynced,
+  _messageType
+) => {
+  authProtocol.readAuthMessage(
+    decoder,
+    provider.doc,
+    (_ydoc, reason) => permissionDeniedHandler(provider, reason)
+  )
+}
+
+// @todo - this should depend on awareness.outdatedTime
+const messageReconnectTimeout = 30000
+
+/**
+ * @param {WebsocketProvider} provider
+ * @param {string} reason
+ */
+const permissionDeniedHandler = (provider, reason) =>
+  console.warn(`Permission denied to access ${provider.url}.\n${reason}`)
+
+/**
+ * @param {WebsocketProvider} provider
+ * @param {Uint8Array} buf
+ * @param {boolean} emitSynced
+ * @return {encoding.Encoder}
+ */
+const readMessage = (provider, buf, emitSynced) => {
+  const decoder = decoding.createDecoder(buf)
+  const encoder = encoding.createEncoder()
+  const messageType = decoding.readVarUint(decoder)
+  const messageHandler = provider.messageHandlers[messageType]
+  if (/** @type {any} */ (messageHandler)) {
+    messageHandler(encoder, decoder, provider, emitSynced, messageType)
+  } else {
+    console.error('Unable to compute message')
+  }
+  return encoder
+}
+
+/**
+ * @param {WebsocketProvider} provider
+ */
+const setupWS = (provider) => {
+  if (provider.shouldConnect && provider.ws === null) {
+    const websocket = new provider._WS(provider.url)
+    websocket.binaryType = 'arraybuffer'
+    provider.ws = websocket
+    provider.wsconnecting = true
+    provider.wsconnected = false
+    provider.synced = false
+
+    websocket.onmessage = (event) => {
+      provider.wsLastMessageReceived = time.getUnixTime()
+      const encoder = readMessage(provider, new Uint8Array(event.data), true)
+      if (encoding.length(encoder) > 1) {
+        websocket.send(encoding.toUint8Array(encoder))
+      }
+    }
+    websocket.onerror = (event) => {
+      provider.emit('connection-error', [event, provider])
+    }
+    websocket.onclose = (event) => {
+      provider.emit('connection-close', [event, provider])
+      provider.ws = null
+      provider.wsconnecting = false
+      if (provider.wsconnected) {
+        provider.wsconnected = false
+        provider.synced = false
+        // update awareness (all users except local left)
+        awarenessProtocol.removeAwarenessStates(
+          provider.awareness,
+          Array.from(provider.awareness.getStates().keys()).filter((client) =>
+            client !== provider.doc.clientID
+          ),
+          provider
+        )
+        provider.emit('status', [{
+          status: 'disconnected'
+        }])
+      } else {
+        provider.wsUnsuccessfulReconnects++
+      }
+      // Start with no reconnect timeout and increase timeout by
+      // using exponential backoff starting with 100ms
+      setTimeout(
+        setupWS,
+        math.min(
+          math.pow(2, provider.wsUnsuccessfulReconnects) * 100,
+          provider.maxBackoffTime
+        ),
+        provider
+      )
+    }
+    websocket.onopen = () => {
+      provider.wsLastMessageReceived = time.getUnixTime()
+      provider.wsconnecting = false
+      provider.wsconnected = true
+      provider.wsUnsuccessfulReconnects = 0
+      provider.emit('status', [{
+        status: 'connected'
+      }])
+      // always send sync step 1 when connected
+      const encoder = encoding.createEncoder()
+      encoding.writeVarUint(encoder, messageSync)
+      syncProtocol.writeSyncStep1(encoder, provider.doc)
+      websocket.send(encoding.toUint8Array(encoder))
+      // broadcast local awareness state
+      if (provider.awareness.getLocalState() !== null) {
+        const encoderAwarenessState = encoding.createEncoder()
+        encoding.writeVarUint(encoderAwarenessState, messageAwareness)
+        encoding.writeVarUint8Array(
+          encoderAwarenessState,
+          awarenessProtocol.encodeAwarenessUpdate(provider.awareness, [
+            provider.doc.clientID
+          ])
+        )
+        websocket.send(encoding.toUint8Array(encoderAwarenessState))
+      }
+    }
+    provider.emit('status', [{
+      status: 'connecting'
+    }])
+  }
+}
+
+/**
+ * @param {WebsocketProvider} provider
+ * @param {ArrayBuffer} buf
+ */
+const broadcastMessage = (provider, buf) => {
+  const ws = provider.ws
+  if (provider.wsconnected && ws && ws.readyState === ws.OPEN) {
+    ws.send(buf)
+  }
+  if (provider.bcconnected) {
+    bc.publish(provider.bcChannel, buf, provider)
+  }
+}
+
+/**
+ * Websocket Provider for Yjs. Creates a websocket connection to sync the shared document.
+ * The document name is attached to the provided url. I.e. the following example
+ * creates a websocket connection to http://localhost:1234/my-document-name
+ *
+ * @example
+ *   import * as Y from 'yjs'
+ *   import { WebsocketProvider } from 'y-websocket'
+ *   const doc = new Y.Doc()
+ *   const provider = new WebsocketProvider('http://localhost:1234', 'my-document-name', doc)
+ *
+ * @extends {Observable<string>}
+ */
+export class WebsocketProvider extends Observable {
+  /**
+   * @param {string} serverUrl
+   * @param {string} roomname
+   * @param {Y.Doc} doc
+   * @param {object} opts
+   * @param {boolean} [opts.connect]
+   * @param {awarenessProtocol.Awareness} [opts.awareness]
+   * @param {Object<string,string>} [opts.params]
+   * @param {typeof WebSocket} [opts.WebSocketPolyfill] Optionall provide a WebSocket polyfill
+   * @param {number} [opts.resyncInterval] Request server state every `resyncInterval` milliseconds
+   * @param {number} [opts.maxBackoffTime] Maximum amount of time to wait before trying to reconnect (we try to reconnect using exponential backoff)
+   * @param {boolean} [opts.disableBc] Disable cross-tab BroadcastChannel communication
+   */
+  constructor (serverUrl, roomname, doc, {
+    connect = true,
+    awareness = new awarenessProtocol.Awareness(doc),
+    params = {},
+    WebSocketPolyfill = WebSocket,
+    resyncInterval = -1,
+    maxBackoffTime = 2500,
+    disableBc = false
+  } = {}) {
+    super()
+    // ensure that url is always ends with /
+    while (serverUrl[serverUrl.length - 1] === '/') {
+      serverUrl = serverUrl.slice(0, serverUrl.length - 1)
+    }
+    const encodedParams = url.encodeQueryParams(params)
+    this.maxBackoffTime = maxBackoffTime
+    this.bcChannel = serverUrl + '/' + roomname
+    this.url = serverUrl + '/' + roomname +
+      (encodedParams.length === 0 ? '' : '?' + encodedParams)
+    this.roomname = roomname
+    this.doc = doc
+    this._WS = WebSocketPolyfill
+    this.awareness = awareness
+    this.wsconnected = false
+    this.wsconnecting = false
+    this.bcconnected = false
+    this.disableBc = disableBc
+    this.wsUnsuccessfulReconnects = 0
+    this.messageHandlers = messageHandlers.slice()
+    /**
+     * @type {boolean}
+     */
+    this._synced = false
+    /**
+     * @type {WebSocket?}
+     */
+    this.ws = null
+    this.wsLastMessageReceived = 0
+    /**
+     * Whether to connect to other peers or not
+     * @type {boolean}
+     */
+    this.shouldConnect = connect
+
+    /**
+     * @type {number}
+     */
+    this._resyncInterval = 0
+    if (resyncInterval > 0) {
+      this._resyncInterval = /** @type {any} */ (setInterval(() => {
+        if (this.ws && this.ws.readyState === WebSocket.OPEN) {
+          // resend sync step 1
+          const encoder = encoding.createEncoder()
+          encoding.writeVarUint(encoder, messageSync)
+          syncProtocol.writeSyncStep1(encoder, doc)
+          this.ws.send(encoding.toUint8Array(encoder))
+        }
+      }, resyncInterval))
+    }
+
+    /**
+     * @param {ArrayBuffer} data
+     * @param {any} origin
+     */
+    this._bcSubscriber = (data, origin) => {
+      if (origin !== this) {
+        const encoder = readMessage(this, new Uint8Array(data), false)
+        if (encoding.length(encoder) > 1) {
+          bc.publish(this.bcChannel, encoding.toUint8Array(encoder), this)
+        }
+      }
+    }
+    /**
+     * Listens to Yjs updates and sends them to remote peers (ws and broadcastchannel)
+     * @param {Uint8Array} update
+     * @param {any} origin
+     */
+    this._updateHandler = (update, origin) => {
+      if (origin !== this) {
+        const encoder = encoding.createEncoder()
+        encoding.writeVarUint(encoder, messageSync)
+        syncProtocol.writeUpdate(encoder, update)
+        broadcastMessage(this, encoding.toUint8Array(encoder))
+      }
+    }
+    this.doc.on('update', this._updateHandler)
+    /**
+     * @param {any} changed
+     * @param {any} _origin
+     */
+    this._awarenessUpdateHandler = ({ added, updated, removed }, _origin) => {
+      const changedClients = added.concat(updated).concat(removed)
+      const encoder = encoding.createEncoder()
+      encoding.writeVarUint(encoder, messageAwareness)
+      encoding.writeVarUint8Array(
+        encoder,
+        awarenessProtocol.encodeAwarenessUpdate(awareness, changedClients)
+      )
+      broadcastMessage(this, encoding.toUint8Array(encoder))
+    }
+    this._exitHandler = () => {
+      awarenessProtocol.removeAwarenessStates(
+        this.awareness,
+        [doc.clientID],
+        'app closed'
+      )
+    }
+    if (env.isNode && typeof process !== 'undefined') {
+      process.on('exit', this._exitHandler)
+    }
+    awareness.on('update', this._awarenessUpdateHandler)
+    this._checkInterval = /** @type {any} */ (setInterval(() => {
+      if (
+        this.wsconnected &&
+        messageReconnectTimeout <
+          time.getUnixTime() - this.wsLastMessageReceived
+      ) {
+        // no message received in a long time - not even your own awareness
+        // updates (which are updated every 15 seconds)
+        /** @type {WebSocket} */ (this.ws).close()
+      }
+    }, messageReconnectTimeout / 10))
+    if (connect) {
+      this.connect()
+    }
+  }
+
+  /**
+   * @type {boolean}
+   */
+  get synced () {
+    return this._synced
+  }
+
+  set synced (state) {
+    if (this._synced !== state) {
+      this._synced = state
+      this.emit('synced', [state])
+      this.emit('sync', [state])
+    }
+  }
+
+  destroy () {
+    if (this._resyncInterval !== 0) {
+      clearInterval(this._resyncInterval)
+    }
+    clearInterval(this._checkInterval)
+    this.disconnect()
+    if (env.isNode && typeof process !== 'undefined') {
+      process.off('exit', this._exitHandler)
+    }
+    this.awareness.off('update', this._awarenessUpdateHandler)
+    this.doc.off('update', this._updateHandler)
+    super.destroy()
+  }
+
+  connectBc () {
+    if (this.disableBc) {
+      return
+    }
+    if (!this.bcconnected) {
+      bc.subscribe(this.bcChannel, this._bcSubscriber)
+      this.bcconnected = true
+    }
+    // send sync step1 to bc
+    // write sync step 1
+    const encoderSync = encoding.createEncoder()
+    encoding.writeVarUint(encoderSync, messageSync)
+    syncProtocol.writeSyncStep1(encoderSync, this.doc)
+    bc.publish(this.bcChannel, encoding.toUint8Array(encoderSync), this)
+    // broadcast local state
+    const encoderState = encoding.createEncoder()
+    encoding.writeVarUint(encoderState, messageSync)
+    syncProtocol.writeSyncStep2(encoderState, this.doc)
+    bc.publish(this.bcChannel, encoding.toUint8Array(encoderState), this)
+    // write queryAwareness
+    const encoderAwarenessQuery = encoding.createEncoder()
+    encoding.writeVarUint(encoderAwarenessQuery, messageQueryAwareness)
+    bc.publish(
+      this.bcChannel,
+      encoding.toUint8Array(encoderAwarenessQuery),
+      this
+    )
+    // broadcast local awareness state
+    const encoderAwarenessState = encoding.createEncoder()
+    encoding.writeVarUint(encoderAwarenessState, messageAwareness)
+    encoding.writeVarUint8Array(
+      encoderAwarenessState,
+      awarenessProtocol.encodeAwarenessUpdate(this.awareness, [
+        this.doc.clientID
+      ])
+    )
+    bc.publish(
+      this.bcChannel,
+      encoding.toUint8Array(encoderAwarenessState),
+      this
+    )
+  }
+
+  disconnectBc () {
+    // broadcast message with local awareness state set to null (indicating disconnect)
+    const encoder = encoding.createEncoder()
+    encoding.writeVarUint(encoder, messageAwareness)
+    encoding.writeVarUint8Array(
+      encoder,
+      awarenessProtocol.encodeAwarenessUpdate(this.awareness, [
+        this.doc.clientID
+      ], new Map())
+    )
+    broadcastMessage(this, encoding.toUint8Array(encoder))
+    if (this.bcconnected) {
+      bc.unsubscribe(this.bcChannel, this._bcSubscriber)
+      this.bcconnected = false
+    }
+  }
+
+  disconnect () {
+    this.shouldConnect = false
+    this.disconnectBc()
+    if (this.ws !== null) {
+      this.ws.close()
+    }
+  }
+
+  connect () {
+    this.shouldConnect = true
+    if (!this.wsconnected && this.ws === null) {
+      setupWS(this)
+      this.connectBc()
+    }
+  }
+}