Add minimum interval between reconnects

Protects against clients that disconnect right after connection, since the backoff retry won't come into play.

Author: paulocsanz

README.md

@@ -103,6 +103,8 @@ wsOpts = {
   awareness: new awarenessProtocol.Awareness(ydoc),
   // Specify the maximum amount to wait between reconnects (we use exponential backoff).
   maxBackoffTime: 2500
+  // Specify the minimum amount to wait between reconnects if the previous connection succeeded but got closed right after.
+  minRetryInterval: 2500
 }
 ```
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "y-websocket",
-  "version": "3.0.0",
+  "version": "3.1.0",
   "description": "Websockets provider for Yjs",
   "main": "./dist/y-websocket.cjs",
   "module": "./src/y-websocket.js",

src/y-websocket.js

@@ -172,6 +172,12 @@ const closeWebsocketConnection = (provider, ws, event) => {
  * @param {WebsocketProvider} provider
  */
 const setupWS = (provider) => {
+  const timeout = provider.lastConnectAt ? Date.now() - provider.lastConnectAt.getTime() : provider.minRetryInterval
+  if (timeout < provider.minRetryInterval && provider.wsUnsuccessfulReconnects === 0) {
+    setTimeout(setupWS, timeout, provider)
+    return
+  }
+
   if (provider.shouldConnect && provider.ws === null) {
     const websocket = new provider._WS(provider.url, provider.protocols)
     websocket.binaryType = 'arraybuffer'
@@ -194,6 +200,7 @@ const setupWS = (provider) => {
       closeWebsocketConnection(provider, websocket, event)
     }
     websocket.onopen = () => {
+      provider.lastConnectAt = new Date()
       provider.wsLastMessageReceived = time.getUnixTime()
       provider.wsconnecting = false
       provider.wsconnected = true
@@ -265,6 +272,7 @@ export class WebsocketProvider extends ObservableV2 {
    * @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 {number} [opts.minRetryInterval] Minimum mount of time to wait between reconnects if the previous connection succeeded but got closed right after.
    * @param {boolean} [opts.disableBc] Disable cross-tab BroadcastChannel communication
    */
   constructor (serverUrl, roomname, doc, {
@@ -275,6 +283,7 @@ export class WebsocketProvider extends ObservableV2 {
     WebSocketPolyfill = WebSocket,
     resyncInterval = -1,
     maxBackoffTime = 2500,
+    minRetryInterval = 2500,
     disableBc = false
   } = {}) {
     super()
@@ -285,6 +294,7 @@ export class WebsocketProvider extends ObservableV2 {
     this.serverUrl = serverUrl
     this.bcChannel = serverUrl + '/' + roomname
     this.maxBackoffTime = maxBackoffTime
+    this.minRetryInterval = minRetryInterval
     /**
      * The specified url parameters. This can be safely updated. The changed parameters will be used
      * when a new connection is established.
@@ -301,6 +311,7 @@ export class WebsocketProvider extends ObservableV2 {
     this.bcconnected = false
     this.disableBc = disableBc
     this.wsUnsuccessfulReconnects = 0
+    this.lastConnectAt = null
     this.messageHandlers = messageHandlers.slice()
     /**
      * @type {boolean}