feat(@angular/cli): add watch flag to serve/e2e

This is useful when you don't want the server to rebuild in the middle of something.

A good example is when running e2e tests. Especially on larger suites, one would prefer to continue working while the build is tested without compromising tests.

This will break tests on angular#4744. They should be adjusted to add the `--watch` flag since they depend on the live reload behaviour during `ng e2e`.

docs/documentation/build.md

@@ -65,7 +65,7 @@ All builds make use of bundling, and using the `--prod` flag in  `ng build --pro
 or `ng serve --prod` will also make use of uglifying and tree-shaking functionality.
 
 ## Options
-`--watch` (`-w`) flag to run builds when files change
+`--watch` (`-w`) rebuild when files change
 
 `--target` (`-t`) define the build target
 

docs/documentation/serve.md

@@ -6,6 +6,8 @@
 `ng serve` builds the application and starts a web server
 
 ## Options
+`--watch` (`-w`) rebuild when files change
+
 `--port` (`-p`) port to serve the application on
 
 `--host` (`-H`) host where to listen

packages/@angular/cli/commands/build.ts

@@ -28,6 +28,7 @@ export const baseBuildCommandOptions: any = [
   { name: 'i18n-format', type: String },
   { name: 'locale', type: String },
   { name: 'extract-css', type: Boolean, aliases: ['ec'] },
+  { name: 'watch', type: Boolean, aliases: ['w'] },
   {
     name: 'output-hashing',
     type: String,
@@ -44,7 +45,6 @@ export const baseBuildCommandOptions: any = [
 ];
 
 export interface BuildTaskOptions extends BuildOptions {
-  watch?: boolean;
   statsJson?: boolean;
 }
 
@@ -54,13 +54,18 @@ const BuildCommand = Command.extend({
   aliases: ['b'],
 
   availableOptions: baseBuildCommandOptions.concat([
-    { name: 'watch', type: Boolean, default: false, aliases: ['w'] },
     { name: 'stats-json', type: Boolean, default: false }
   ]),
 
   run: function (commandOptions: BuildTaskOptions) {
     const project = this.project;
 
+    const additionalDefaults: any = {
+      watch: false
+    };
+
+    commandOptions = Object.assign({}, additionalDefaults, commandOptions);
+
     // Check angular version.
     Version.assertAngularVersionIs2_3_1OrHigher(project.root);
 

packages/@angular/cli/commands/e2e.ts

@@ -32,6 +32,12 @@ const E2eCommand = Command.extend({
     const E2eTask = require('../tasks/e2e').E2eTask;
     this.project.ngConfig = this.project.ngConfig || CliConfig.fromProject();
 
+    const additionalDefaults: any = {
+      watch: false
+    };
+
+    commandOptions = Object.assign({}, additionalDefaults, commandOptions);
+
     const e2eTask = new E2eTask({
       ui: this.ui,
       project: this.project

packages/@angular/cli/commands/serve.ts

@@ -97,6 +97,12 @@ const ServeCommand = Command.extend({
   run: function (commandOptions: ServeTaskOptions) {
     const ServeTask = require('../tasks/serve').default;
 
+    const additionalDefaults: any = {
+      watch: true
+    };
+
+    commandOptions = Object.assign({}, additionalDefaults, commandOptions);
+
     Version.assertAngularVersionIs2_3_1OrHigher(this.project.root);
     commandOptions.liveReloadHost = commandOptions.liveReloadHost || commandOptions.host;
 

packages/@angular/cli/models/build-options.ts

@@ -13,6 +13,7 @@ export interface BuildOptions {
   i18nFormat?: string;
   locale?: string;
   extractCss?: boolean;
+  watch?: boolean;
   outputHashing?: string;
   poll?: number;
 }

packages/@angular/cli/tasks/serve.ts

@@ -65,6 +65,19 @@ export default Task.extend({
     }
     if (!webpackConfig.entry.main) { webpackConfig.entry.main = []; }
     webpackConfig.entry.main.unshift(...entryPoints);
+
+    if (!serveTaskOptions.watch) {
+      // There's no option to turn off file watching in webpack-dev-server, but
+      // we can override the file watcher instead.
+      webpackConfig.plugins.unshift({
+        apply: (compiler: any) => {
+          compiler.plugin('after-environment', () => {
+            compiler.watchFileSystem = { watch: () => {} };
+          });
+        }
+      });
+    }
+
     webpackCompiler = webpack(webpackConfig);
 
     if (rebuildDoneCb) {

packages/@ngtools/webpack/src/plugin.ts

@@ -242,9 +242,11 @@ export class AotPlugin implements Tapable {
       this._firstRun = false;
       this._diagnoseFiles = {};
 
-      compiler.watchFileSystem.watcher.once('aggregated', (changes: string[]) => {
-        changes.forEach((fileName: string) => this._compilerHost.invalidate(fileName));
-      });
+      if (compiler.watchFileSystem.watcher) {
+        compiler.watchFileSystem.watcher.once('aggregated', (changes: string[]) => {
+          changes.forEach((fileName: string) => this._compilerHost.invalidate(fileName));
+        });
+      }
     });
 
     // Add lazy modules to the context module for @angular/core/src/linker

tests/e2e/tests/build/watch.ts

@@ -0,0 +1,33 @@
+import {
+  killAllProcesses,
+  exec,
+  waitForAnyProcessOutputToMatch,
+  silentExecAndWaitForOutputToMatch
+} from '../../utils/process';
+import { expectToFail } from '../../utils/utils';
+
+
+const webpackGoodRegEx = /webpack: bundle is now VALID|webpack: Compiled successfully./;
+
+export default function () {
+  if (process.platform.startsWith('win')) {
+    return Promise.resolve();
+  }
+
+  return silentExecAndWaitForOutputToMatch('ng', ['serve'], webpackGoodRegEx)
+    // Should trigger a rebuild.
+    .then(() => exec('touch', 'src/main.ts'))
+    .then(() => waitForAnyProcessOutputToMatch(webpackGoodRegEx, 5000))
+    .then(() => killAllProcesses(), (err: any) => {
+      killAllProcesses();
+      throw err;
+    })
+    .then(() => silentExecAndWaitForOutputToMatch('ng', ['serve', '--no-watch'], webpackGoodRegEx))
+    // Should not trigger a rebuild when not watching files.
+    .then(() => exec('touch', 'src/main.ts'))
+    .then(() => expectToFail(() => waitForAnyProcessOutputToMatch(webpackGoodRegEx, 5000)))
+    .then(() => killAllProcesses(), (err: any) => {
+      killAllProcesses();
+      throw err;
+    })
+}