Merge pull request #242 from minrk/hardcode-widgets-js

load widget extension in js

notebook/static/base/js/utils.js

@@ -842,6 +842,7 @@ define([
     };
     
     var utils = {
+        load_extension: load_extension,
         load_extensions: load_extensions,
         load_extensions_from_config: load_extensions_from_config,
         regex_split : regex_split,

notebook/static/notebook/js/main.js

@@ -51,10 +51,8 @@ require([
     "use strict";
 
     // BEGIN HARDCODED WIDGETS HACK
-    // Don't include in above require call, avoiding r.js
-    // and crash on import failure.
-    require(['nbextensions/widgets/notebook/js/extension'], function(){}, function(err) {
-        console.error('ipywidgets package not installed.  Widgets are not available.');
+    utils.load_extension('widgets/notebook/js/extension').catch(function () {
+        console.warn('ipywidgets package not installed.  Widgets are not available.');
     });
     // END HARDCODED WIDGETS HACK