feat(@angular/cli): name lazy chunks

Before:
```
$ ng build --no-progress
Hash: ff03df269349b817eef4
Time: 11202ms
chunk    {0} 0.chunk.js, 0.chunk.js.map 1.61 kB {1} {3} [rendered]
chunk    {1} 1.chunk.js, 1.chunk.js.map 1.46 kB {0} {3} [rendered]
chunk    {2} polyfills.bundle.js, polyfills.bundle.js.map (polyfills) 160 kB {6} [initial] [rendered]
chunk    {3} main.bundle.js, main.bundle.js.map (main) 6.38 kB {5} [initial] [rendered]
chunk    {4} styles.bundle.js, styles.bundle.js.map (styles) 10.5 kB {6} [initial] [rendered]
chunk    {5} vendor.bundle.js, vendor.bundle.js.map (vendor) 2.16 MB [initial] [rendered]
chunk    {6} inline.bundle.js, inline.bundle.js.map (inline) 0 bytes [entry] [rendered]
```

After:
```
$ ng build --no-progress
Hash: 2bc12a89f40f3b4818b5
Time: 9613ms
chunk {feature.module} feature.module.chunk.js, feature.module.chunk.js.map 1.46 kB {lazy.module} {main} [rendered]
chunk {inline} inline.bundle.js, inline.bundle.js.map (inline) 0 bytes [entry] [rendered]
chunk {lazy.module} lazy.module.chunk.js, lazy.module.chunk.js.map 1.61 kB {feature.module} {main} [rendered]
chunk {main} main.bundle.js, main.bundle.js.map (main) 6.38 kB {vendor} [initial] [rendered]
chunk {polyfills} polyfills.bundle.js, polyfills.bundle.js.map (polyfills) 160 kB {inline} [initial] [rendered]
chunk {styles} styles.bundle.js, styles.bundle.js.map (styles) 10.5 kB {inline} [initial] [rendered]
chunk {vendor} vendor.bundle.js, vendor.bundle.js.map (vendor) 2.16 MB [initial] [rendered]
```

Fix angular#6700

Author: filipesilva

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

@@ -1,6 +1,7 @@
 import * as webpack from 'webpack';
 import * as path from 'path';
 import { GlobCopyWebpackPlugin } from '../../plugins/glob-copy-webpack-plugin';
+import { NamedLazyChunksWebpackPlugin } from '../../plugins/named-lazy-chunks-webpack-plugin';
 import { extraEntryParser, getOutputHashFormat } from './utils';
 import { WebpackConfigOptions } from '../webpack-config';
 
@@ -109,7 +110,8 @@ export function getCommonConfig(wco: WebpackConfigOptions) {
       ].concat(extraRules)
     },
     plugins: [
-      new webpack.NoEmitOnErrorsPlugin()
+      new webpack.NoEmitOnErrorsPlugin(),
+      new NamedLazyChunksWebpackPlugin(),
     ].concat(extraPlugins),
     node: {
       fs: 'empty',

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

@@ -97,7 +97,7 @@ export const getProdConfig = function (wco: WebpackConfigOptions) {
       new webpack.EnvironmentPlugin({
         'NODE_ENV': 'production'
       }),
-      new (<any>webpack).HashedModuleIdsPlugin(),
+      new webpack.HashedModuleIdsPlugin(),
       new webpack.optimize.UglifyJsPlugin(<any>{
         mangle: { screw_ie8: true },
         compress: { screw_ie8: true, warnings: buildOptions.verbose },

packages/@angular/cli/plugins/named-lazy-chunks-webpack-plugin.ts

@@ -0,0 +1,41 @@
+import * as webpack from 'webpack';
+
+
+// This just extends webpack.NamedChunksPlugin to prevent name collisions.
+export class NamedLazyChunksWebpackPlugin extends webpack.NamedChunksPlugin {
+  constructor() {
+    const nameMap = new Map();
+    // Append a dot and number if the name already exists.
+    const getNextName = (baseName: string) => {
+      let num: number | null = null;
+      const name = () => num !== null ? `${baseName}.${num}` : baseName;
+      while (nameMap.has(name())) {
+        num = num ? num++ : 0;
+      }
+      nameMap.set(name(), true);
+      return name();
+    };
+
+    const nameResolver = (chunk: any) => {
+      // Entry chunks have a name already, use it.
+      if (chunk.name) {
+        return chunk.name;
+      }
+
+      // Try to figure out if it's a lazy loaded route.
+      if (chunk.blocks
+        && chunk.blocks.length > 0
+        && chunk.blocks[0].dependencies
+        && chunk.blocks[0].dependencies.length > 0
+        && chunk.blocks[0].dependencies[0].lazyRouteChunkName
+      ) {
+        // lazyRouteChunkName was added by @ngtools/webpack.
+        return getNextName(chunk.blocks[0].dependencies[0].lazyRouteChunkName);
+      }
+
+      return null;
+    };
+
+    super(nameResolver);
+  }
+}

packages/@angular/cli/plugins/webpack.js

@@ -6,5 +6,7 @@ module.exports = {
   GlobCopyWebpackPlugin: require('../plugins/glob-copy-webpack-plugin').GlobCopyWebpackPlugin,
   SuppressExtractedTextChunksWebpackPlugin:
     require('../plugins/suppress-entry-chunks-webpack-plugin')
-      .SuppressExtractedTextChunksWebpackPlugin
+      .SuppressExtractedTextChunksWebpackPlugin,
+  NamedLazyChunksWebpackPlugin:
+    require('../plugins/named-lazy-chunks-webpack-plugin').NamedLazyChunksWebpackPlugin
 };

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

@@ -175,6 +175,7 @@ class JsonWebpackSerializer {
           this._addImport('webpack.optimize', 'UglifyJsPlugin');
           break;
         case angularCliPlugins.BaseHrefWebpackPlugin:
+        case angularCliPlugins.NamedLazyChunksWebpackPlugin:
         case angularCliPlugins.SuppressExtractedTextChunksWebpackPlugin:
           this._addImport('@angular/cli/plugins/webpack', plugin.constructor.name);
           break;

packages/@angular/cli/webpack-custom-typings.d.ts

@@ -0,0 +1,10 @@
+import * as webpack from 'webpack';
+
+declare module 'webpack' {
+  export class NamedChunksPlugin {
+    constructor(nameResolver: (chunk: any) => string | null);
+  }
+  export class HashedModuleIdsPlugin {
+    constructor();
+  }
+}

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

@@ -310,7 +310,11 @@ export class AotPlugin implements Tapable {
               .map((key) => {
                 const value = this._lazyRoutes[key];
                 if (value !== null) {
-                  return new ContextElementDependency(value, key);
+                  const dep = new ContextElementDependency(value, key);
+                  // lazyRouteChunkName is used by webpack.NamedChunksPlugin to give the
+                  // lazy loaded chunk a name.
+                  dep.lazyRouteChunkName = path.basename(key, '.ts');
+                  return dep;
                 } else {
                   return null;
                 }

tests/e2e/tests/misc/lazy-module.ts

@@ -17,12 +17,17 @@ export default function() {
       RouterModule.forRoot([{ path: "lazy1", loadChildren: "./lazy/lazy.module#LazyModule" }])
       `, '@angular/router'))
     .then(() => ng('build'))
-    .then(() => readdirSync('dist').length)
-    .then(currentNumberOfDistFiles => {
+    .then(() => readdirSync('dist'))
+    .then((distFiles) => {
+      const currentNumberOfDistFiles = distFiles.length;
       if (oldNumberOfFiles >= currentNumberOfDistFiles) {
         throw new Error('A bundle for the lazy module was not created.');
       }
       oldNumberOfFiles = currentNumberOfDistFiles;
+
+      if (!distFiles.includes('lazy.module.chunk.js')){
+        throw new Error('The bundle for the lazy module did not have a name.');
+      }
     })
     // verify System.import still works
     .then(() => writeFile('src/app/lazy-file.ts', ''))