FIX: allow for more than 1 markdown editor instances

app/assets/javascripts/discourse/components/pagedown-editor.js.es6

@@ -1,21 +1,23 @@
+import { observes, on } from 'ember-addons/ember-computed-decorators';
 import loadScript from 'discourse/lib/load-script';
 
 export default Ember.Component.extend({
   classNameBindings: [':pagedown-editor'],
 
-  _initializeWmd: function() {
-    const self = this;
-    loadScript('defer/html-sanitizer-bundle').then(function() {
-      self.$('.wmd-input').data('init', true);
-      self._editor = Discourse.Markdown.createEditor({ containerElement: self.element });
-      self._editor.run();
-      Ember.run.scheduleOnce('afterRender', self, self._refreshPreview);
+  @on("didInsertElement")
+  _initializeWmd() {
+    loadScript('defer/html-sanitizer-bundle').then(() => {
+      this.$('.wmd-input').data('init', true);
+      this._editor = Discourse.Markdown.createEditor({ containerElement: this.element });
+      this._editor.run();
+      Ember.run.scheduleOnce('afterRender', this, this._refreshPreview);
     });
-  }.on('didInsertElement'),
+  },
 
-  observeValue: function() {
+  @observes("value")
+  observeValue() {
     Ember.run.scheduleOnce('afterRender', this, this._refreshPreview);
-  }.observes('value'),
+  },
 
   _refreshPreview() {
     this._editor.refreshPreview();

app/assets/javascripts/discourse/lib/Markdown.Editor.js

@@ -306,7 +306,8 @@
     // end of Chunks
 
     function firstByClass(doc, containerElement, className) {
-      var elements = doc.getElementsByClassName(className);
+      var container = containerElement || doc;
+      var elements = container.getElementsByClassName(className);
       if (elements && elements.length) {
         return elements[0];
       }

app/assets/javascripts/discourse/templates/components/pagedown-editor.hbs

@@ -1,4 +1,3 @@
 <div class='wmd-button-bar'></div>
 {{textarea value=value class="wmd-input"}}
-<div class="wmd-preview preview {{unless value 'hidden'}}">
-</div>
+<div class="wmd-preview preview {{unless value 'hidden'}}"></div>

app/assets/javascripts/discourse/views/composer.js.es6

@@ -246,7 +246,7 @@ const ComposerView = Ember.View.extend(Ember.Evented, {
     });
 
 
-    const options ={
+    const options = {
       containerElement: this.element,
       lookupAvatarByPostNumber(postNumber, topicId) {
         const posts = controller.get('controllers.topic.model.postStream.posts');