From 73b24ae2251f144d8bacd93492285085add34577 Mon Sep 17 00:00:00 2001
From: Michael Telatynski <7t3chguy@gmail.com>
Date: Wed, 19 May 2021 09:24:46 +0100
Subject: [PATCH] move WatchManager over to an ES6 Map

---
 src/settings/WatchManager.ts | 44 ++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

diff --git a/src/settings/WatchManager.ts b/src/settings/WatchManager.ts
index ea2f158ef6..56f911f180 100644
--- a/src/settings/WatchManager.ts
+++ b/src/settings/WatchManager.ts
@@ -18,11 +18,7 @@ import { SettingLevel } from "./SettingLevel";
 
 export type CallbackFn = (changedInRoomId: string, atLevel: SettingLevel, newValAtLevel: any) => void;
 
-const IRRELEVANT_ROOM: string = null;
-
-interface RoomWatcherMap {
-    [roomId: string]: CallbackFn[];
-}
+const IRRELEVANT_ROOM = Symbol("irrelevant-room");
 
 /**
  * Generalized management class for dealing with watchers on a per-handler (per-level)
@@ -30,25 +26,25 @@ interface RoomWatcherMap {
  * class, which are then proxied outwards to any applicable watchers.
  */
 export class WatchManager {
-    private watchers: {[settingName: string]: RoomWatcherMap} = {};
+    private watchers = new Map<string, Map<string | symbol, CallbackFn[]>>(); // settingName -> roomId -> CallbackFn[]
 
     // Proxy for handlers to delegate changes to this manager
     public watchSetting(settingName: string, roomId: string | null, cb: CallbackFn) {
-        if (!this.watchers[settingName]) this.watchers[settingName] = {};
-        if (!this.watchers[settingName][roomId]) this.watchers[settingName][roomId] = [];
-        this.watchers[settingName][roomId].push(cb);
+        if (!this.watchers.has(settingName)) this.watchers.set(settingName, new Map());
+        if (!this.watchers.get(settingName).has(roomId)) this.watchers.get(settingName).set(roomId, []);
+        this.watchers.get(settingName).get(roomId).push(cb);
     }
 
     // Proxy for handlers to delegate changes to this manager
     public unwatchSetting(cb: CallbackFn) {
-        for (const settingName of Object.keys(this.watchers)) {
-            for (const roomId of Object.keys(this.watchers[settingName])) {
+        this.watchers.forEach((map) => {
+            map.forEach((callbacks) => {
                 let idx;
-                while ((idx = this.watchers[settingName][roomId].indexOf(cb)) !== -1) {
-                    this.watchers[settingName][roomId].splice(idx, 1);
+                while ((idx = callbacks.indexOf(cb)) !== -1) {
+                    callbacks.splice(idx, 1);
                 }
-            }
-        }
+            });
+        });
     }
 
     public notifyUpdate(settingName: string, inRoomId: string | null, atLevel: SettingLevel, newValueAtLevel: any) {
@@ -56,21 +52,21 @@ export class WatchManager {
         // we also don't have a reliable way to get the old value of a setting. Instead, we'll just
         // let it fall through regardless and let the receiver dedupe if they want to.
 
-        if (!this.watchers[settingName]) return;
+        if (!this.watchers.has(settingName)) return;
 
-        const roomWatchers = this.watchers[settingName];
+        const roomWatchers = this.watchers.get(settingName);
         const callbacks = [];
 
-        if (inRoomId !== null && roomWatchers[inRoomId]) {
-            callbacks.push(...roomWatchers[inRoomId]);
+        if (inRoomId !== null && roomWatchers.has(inRoomId)) {
+            callbacks.push(...roomWatchers.get(inRoomId));
         }
 
         if (!inRoomId) {
-            // Fire updates to all the individual room watchers too, as they probably
-            // care about the change higher up.
-            callbacks.push(...Object.values(roomWatchers).flat(1));
-        } else if (roomWatchers[IRRELEVANT_ROOM]) {
-            callbacks.push(...roomWatchers[IRRELEVANT_ROOM]);
+            // Fire updates to all the individual room watchers too, as they probably care about the change higher up.
+            const callbacks = Array.from(roomWatchers.values()).flat(1);
+            callbacks.push(...callbacks);
+        } else if (roomWatchers.has(IRRELEVANT_ROOM)) {
+            callbacks.push(...roomWatchers.get(IRRELEVANT_ROOM));
         }
 
         for (const callback of callbacks) {