From e6465d06462e492eb170503d3454fdcdf2380499 Mon Sep 17 00:00:00 2001
From: Paul Makles <paulmakles@gmail.com>
Date: Thu, 31 Dec 2020 13:04:49 +0000
Subject: [PATCH] Exponential backoff on reconnect.

---
 package.json            |  1 +
 src/Client.ts           |  1 +
 src/tester.ts           | 12 ++++++++++++
 src/websocket/client.ts |  8 +++++++-
 yarn.lock               |  5 +++++
 5 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/package.json b/package.json
index 99cfb6e1..8671832a 100644
--- a/package.json
+++ b/package.json
@@ -8,6 +8,7 @@
   "dependencies": {
     "axios": "^0.19.2",
     "concurrently": "^5.1.0",
+    "exponential-backoff": "^3.1.0",
     "isomorphic-ws": "^4.0.1",
     "lodash": "^4.17.15",
     "tsc-watch": "^4.1.0",
diff --git a/src/Client.ts b/src/Client.ts
index e9c18c83..eb97b20f 100644
--- a/src/Client.ts
+++ b/src/Client.ts
@@ -21,6 +21,7 @@ export interface ClientOptions {
 export declare interface Client {
 	// WebSocket related events.
 	on(event: 'connected', listener: () => void): this;
+	on(event: 'connecting', listener: () => void): this;
     on(event: 'dropped', listener: () => void): this;
 	on(event: 'ready', listener: () => void): this;
 }
diff --git a/src/tester.ts b/src/tester.ts
index 74fb5003..5fc8451b 100644
--- a/src/tester.ts
+++ b/src/tester.ts
@@ -8,6 +8,18 @@ client.on('ready', () => {
     console.log(`Logged in as @${client.user?.username}`);
 });
 
+client.on('connecting', () => {
+    console.log(`Connecting to the notifications server.`);
+});
+
+client.on('connected', () => {
+    console.log(`Connected to notifications server.`);
+});
+
+client.on('dropped', () => {
+    console.log(`Connection dropped.`);
+});
+
 (async () => {
     console.log('Start:', new Date());
 
diff --git a/src/websocket/client.ts b/src/websocket/client.ts
index ef6bc767..80059e57 100644
--- a/src/websocket/client.ts
+++ b/src/websocket/client.ts
@@ -1,4 +1,5 @@
 import WebSocket from 'isomorphic-ws';
+import { backOff } from 'exponential-backoff';
 
 import { Client } from '..';
 import { Auth } from '../api/auth';
@@ -14,7 +15,9 @@ export class WebSocketClient {
         this.client = client;
     }
 
-    connect(): Promise<void> {
+    connect(disallowReconnect?: boolean): Promise<void> {
+        this.client.emit('connecting');
+
         return new Promise((resolve, $reject) => {
             let thrown = false;
             const reject = (err: any) => {
@@ -63,6 +66,9 @@ export class WebSocketClient {
 
             ws.onclose = () => {
                 this.client.emit('dropped');
+                if (!disallowReconnect && this.client.options.autoReconnect) {
+                    backOff(() => this.connect(true)).catch(reject);
+                }
             };
         });
     }
diff --git a/yarn.lock b/yarn.lock
index 8aa849a1..b1c7dde9 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -164,6 +164,11 @@ event-stream@=3.3.4:
     stream-combiner "~0.0.4"
     through "~2.3.1"
 
+exponential-backoff@^3.1.0:
+  version "3.1.0"
+  resolved "https://registry.yarnpkg.com/exponential-backoff/-/exponential-backoff-3.1.0.tgz#9409c7e579131f8bd4b32d7d8094a911040f2e68"
+  integrity sha512-oBuz5SYz5zzyuHINoe9ooePwSu0xApKWgeNzok4hZ5YKXFh9zrQBEM15CXqoZkJJPuI2ArvqjPQd8UKJA753XA==
+
 find-up@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/find-up/-/find-up-3.0.0.tgz#49169f1d7993430646da61ecc5ae355c21c97b73"