From 76730d38d4f839f47c5adc4d3b4852070251aab1 Mon Sep 17 00:00:00 2001
From: Jiiks <jiiks@windowslive.com>
Date: Wed, 31 Jan 2018 15:35:22 +0200
Subject: [PATCH] add dom observer

---
 client/src/index.js  |  2 +-
 client/src/ui/dom.js | 55 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/client/src/index.js b/client/src/index.js
index d43150ea..060eb804 100644
--- a/client/src/index.js
+++ b/client/src/index.js
@@ -14,8 +14,8 @@ import { Events, CssEditor, Globals, PluginManager, ThemeManager } from 'modules
 import { ClientLogger as Logger } from 'common';
 
 class BetterDiscord {
+
     constructor() {
-        window.pom = PluginManager;
         DOM.injectStyle(BdCss, 'bdmain');
         Events.on('global-ready', this.globalReady.bind(this));
     }
diff --git a/client/src/ui/dom.js b/client/src/ui/dom.js
index f7e09916..330ca962 100644
--- a/client/src/ui/dom.js
+++ b/client/src/ui/dom.js
@@ -30,8 +30,63 @@ class BdNode {
     }
 }
 
+class DOMObserver {
+
+    constructor() {
+        this.observe = this.observe.bind(this);
+        this.subscribe = this.subscribe.bind(this);
+        this.observerCallback = this.observerCallback.bind(this);
+        this.observer = new MutationObserver(this.observerCallback);
+    }
+
+    observerCallback(mutations) {
+        this.subscriptions.forEach(sub => {
+            try {
+                const f = mutations.find(sub.filter);
+                if (f) sub.callback(f);
+            } catch (err) { }
+        });
+    }
+
+    observe() {
+        this.observer.observe(this.root, this.options);
+    }
+
+    get root() {
+        return document.getElementById('app-mount');
+    }
+
+    get options() {
+        return { attributes: true, childList: true, subtree: true };
+    }
+
+    get subscriptions() {
+        return this._subscriptions || (this._subscriptions = []);
+    }
+
+    subscribe(id, filter, callback) {
+        if (this.subscriptions.find(sub => sub.id === id)) return;
+        this.subscriptions.push({
+            id,
+            filter,
+            callback
+        });
+    }
+
+    unsubscribe(id) {
+        const index = this.subscriptions.find(sub => sub.id === id);
+        if (index < 0) return;
+        this.subscriptions.splice(index, 1);
+    }
+
+}
+
 class DOM {
 
+    static get observer() {
+        return this._observer || (this._observer = new DOMObserver());
+    }
+
     static get bdHead() {
         return this.getElement('bd-head') || this.createElement('bd-head').appendTo('head');
     }