FIX: Allow `loadScript` to use script tags if the JS library require it.

app/assets/javascripts/admin/components/ace-editor.js.es6

@@ -32,15 +32,7 @@ export default Ember.Component.extend({
   _initEditor: function() {
     const self = this;
 
-    loadScript("/javascripts/ace/ace.js").then(function() {
-
-      // this is a bit weird, unlike $LAB loadScript is not keeping
-      // relative directory which messes stuff up
-      // TODO: correct relative directory and get rid of this
-      _.each(["base","mode","theme","worker"], function(p){
-        ace.config.set(p +"Path", "/javascripts/ace");
-      });
-
+    loadScript("/javascripts/ace/ace.js", { scriptTag: true }).then(function() {
       const editor = ace.edit(self.$('.ace')[0]);
 
       editor.setTheme("ace/theme/chrome");

app/assets/javascripts/discourse/lib/load-script.js.es6

@@ -2,16 +2,42 @@
 
 const _loaded = {};
 
-export default function loadScript(url) {
+function loadWithTag(path, cb) {
+  const head = document.getElementsByTagName('head')[0];
+
+  let s = document.createElement('script');
+  s.src = path;
+  head.appendChild(s);
+
+  s.onload = s.onreadystatechange = function(_, abort) {
+    if (abort || !s.readyState || s.readyState === "loaded" || s.readyState === "complete") {
+      s = s.onload = s.onreadystatechange = null;
+      if (!abort) { cb(); }
+    }
+  };
+}
+
+export default function loadScript(url, opts) {
+  opts = opts || {};
+
   return new Ember.RSVP.Promise(function(resolve) {
     url = Discourse.getURL((assetPath && assetPath(url)) || url);
 
     // If we already loaded this url
     if (_loaded[url]) { return resolve(); }
 
-    $.getScript(url).then(function() {
+    const cb = function() {
       _loaded[url] = true;
       resolve();
-    });
+    };
+
+    // Some javascript depends on the path of where it is loaded (ace editor)
+    // to dynamically load more JS. In that case, add the `scriptTag: true`
+    // option.
+    if (opts.scriptTag) {
+      loadWithTag(url, cb);
+    } else {
+      $.getScript(url).then(cb);
+    }
   });
 }