fix: IE9/10/11 shim for CustomEvent

config/shims_for_IE.js

@@ -0,0 +1,21 @@
+// CustomEvent (IE9/10/11)
+
+try {
+  new window.CustomEvent("test");
+} catch(e) {
+ var CustomEvent = function(event, params) {
+      var evt;
+      params = params || {
+          bubbles: false,
+          cancelable: false,
+          detail: undefined
+      };
+
+      evt = document.createEvent("CustomEvent");
+      evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail);
+      return evt;
+  };
+
+  CustomEvent.prototype = window.Event.prototype;
+  window.CustomEvent = CustomEvent; // expose definition to window
+}

config/webpack/client/test.js

@@ -15,7 +15,7 @@ module.exports = webpackMerge(commonConfig, {
   metadata: METADATA,
   devtool: 'source-map',
 
-  entry: {main: ['./config/spec-imports'].concat(glob.sync('./src/client/**/*.spec.ts'))},
+  entry: {main: ['./config/spec-imports', './config/shims_for_IE.js'].concat(glob.sync('./src/client/**/*.spec.ts'))},
 
   output: {path: helpers.root('dist/spec/client'), filename: '[name].spec.js'},