don't reload when there are errors

Author: filipesilva

packages/@angular/cli/models/webpack-configs/test.ts

@@ -4,7 +4,6 @@ import * as webpack from 'webpack';
 
 import { CliConfig } from '../config';
 import { WebpackTestOptions } from '../webpack-test-config';
-import { KarmaWebpackEmitlessError } from '../../plugins/karma-webpack-emitless-error';
 
 
 /**
@@ -66,7 +65,7 @@ export function getTestConfig(testConfig: WebpackTestOptions) {
         chunks: ['main'],
         minChunks: (module: any) => module.resource && module.resource.startsWith(nodeModules)
       }),
-      new KarmaWebpackEmitlessError()
+      // new KarmaWebpackEmitlessError()
     ].concat(extraPlugins)
   };
 }

packages/@angular/cli/plugins/karma-webpack-emitless-error.ts

@@ -94,7 +94,16 @@ const init: any = (config: any, emitter: any, customFileHandlers: any) => {
   const webpackMiddlewareConfig = {
     noInfo: true, // Hide webpack output because its noisy.
     watchOptions: { poll: testConfig.poll },
-    publicPath: '/_karma_webpack_/'
+    publicPath: '/_karma_webpack_/',
+    stats: { // Also prevent chunk and module display output, cleaner look. Only emit errors.
+      assets: false,
+      colors: true,
+      version: false,
+      hash: false,
+      timings: false,
+      chunks: false,
+      chunkModules: false
+    }
   };
 
   // If Karma is being ran in single run mode, throw errors.
@@ -156,15 +165,19 @@ const init: any = (config: any, emitter: any, customFileHandlers: any) => {
     });
   });
 
-  compiler.plugin('done', () => {
-    emitter.refreshFiles();
-    isBlocked = false;
-    blocked.forEach((cb) => cb());
-    blocked = [];
+  compiler.plugin('done', (stats: any) => {
+    // Don't refresh karma when there are webpack errors.
+    if (stats.compilation.errors.length === 0) {
+      emitter.refreshFiles();
+      isBlocked = false;
+      blocked.forEach((cb) => cb());
+      blocked = [];
+    }
   });
 
   const middleware = new webpackDevMiddleware(compiler, webpackMiddlewareConfig);
 
+  // Forward requests to webpack server.
   customFileHandlers.push({
     urlRegex: /^\/_karma_webpack_\/.*/,
     handler: function handler(req: any, res: any) {