FIX: After uploading an image the selection was not in the correct spot

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

@@ -189,7 +189,7 @@ export default Ember.Component.extend({
       this.setProperties({ uploadProgress: 0, isUploading: false, isCancellable: false });
     }
     if (removePlaceholder) {
-      this.set('composer.reply', this.get('composer.reply').replace(this.get('uploadPlaceholder'), ""));
+      this.appEvents.trigger('composer:replace-text', this.get('uploadPlaceholder'), "");
     }
   },
 
@@ -219,7 +219,6 @@ export default Ember.Component.extend({
 
     $element.on("fileuploadsend", (e, data) => {
       this._validUploads++;
-      // add upload placeholders
       this.appEvents.trigger('composer:insert-text', uploadPlaceholder);
 
       if (data.xhr && data.originalFiles.length === 1) {
@@ -244,7 +243,7 @@ export default Ember.Component.extend({
       if (upload && upload.url) {
         if (!this._xhr || !this._xhr._userCancelled) {
           const markdown = getUploadMarkdown(upload);
-          this.set('composer.reply', this.get('composer.reply').replace(uploadPlaceholder, markdown));
+          this.appEvents.trigger('composer:replace-text', uploadPlaceholder, markdown);
           this._resetUpload(false);
         } else {
           this._resetUpload(true);

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

@@ -215,9 +215,8 @@ export default Ember.Component.extend({
       return false;
     });
 
-    this.appEvents.on('composer:insert-text', text => {
-      this._addText(this._getSelected(), text);
-    });
+    this.appEvents.on('composer:insert-text', text => this._addText(this._getSelected(), text));
+    this.appEvents.on('composer:replace-text', (oldVal, newVal) => this._replaceText(oldVal, newVal));
 
     this._mouseTrap = mouseTrap;
   },
@@ -225,6 +224,7 @@ export default Ember.Component.extend({
   @on('willDestroyElement')
   _shutDown() {
     this.appEvents.off('composer:insert-text');
+    this.appEvents.off('composer:replace-text');
 
     const mouseTrap = this._mouseTrap;
     Object.keys(this.get('toolbar.shortcuts')).forEach(sc => mouseTrap.unbind(sc));
@@ -475,6 +475,15 @@ export default Ember.Component.extend({
     }
   },
 
+  _replaceText(oldVal, newVal) {
+    const val = this.get('value');
+    const loc = val.indexOf(oldVal);
+    if (loc !== -1) {
+      this.set('value', val.replace(oldVal, newVal));
+      this._selectText(loc + newVal.length, 0);
+    }
+  },
+
   _addText(sel, text) {
     const $textarea = this.$('textarea.d-editor-input');
     const insert = `${sel.pre}${text}`;

test/javascripts/components/d-editor-test.js.es6

@@ -596,3 +596,18 @@ componentTest('emoji', {
     });
   }
 });
+
+testCase("replace-text event", function(assert, textarea) {
+
+  this.set('value', "red green blue");
+
+  andThen(() => {
+    this.container.lookup('app-events:main').trigger('composer:replace-text', 'green', 'yellow');
+  });
+
+  andThen(() => {
+    assert.equal(this.get('value'), 'red yellow blue');
+    assert.equal(textarea.selectionStart, 10);
+    assert.equal(textarea.selectionEnd, 10);
+  });
+});