fix(@ngtools/webpack): support webpack loaders in the webpack plugin

This is only useful when using webpack directly. Does not affect the CLI.

Performance is going to be impacted, but we do not type check after the loaders.

TODO: add typechecking if the source we receive from Webpack is different from the host.

Author: hansl

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

@@ -436,15 +436,20 @@ function _diagnoseDeps(reasons: ModuleReason[], plugin: AotPlugin, checked: Set<
 
 
 // Super simple TS transpiler loader for testing / isolated usage. does not type check!
-export function ngcLoader(this: LoaderContext & { _compilation: any }) {
+export function ngcLoader(this: LoaderContext & { _compilation: any }, source: string | null) {
   const cb = this.async();
   const sourceFileName: string = this.resourcePath;
 
   const plugin = this._compilation._ngToolsWebpackPluginInstance as AotPlugin;
   // We must verify that AotPlugin is an instance of the right class.
   if (plugin && plugin instanceof AotPlugin) {
+    if (plugin.compilerHost.readFile(sourceFileName) == source) {
+      // In the case where the source is the same as the one in compilerHost, we don't have
+      // extra TS loaders and there's no need to do any trickery.
+      source = null;
+    }
     const refactor = new TypeScriptFileRefactor(
-      sourceFileName, plugin.compilerHost, plugin.program);
+      sourceFileName, plugin.compilerHost, plugin.program, source);
 
     Promise.resolve()
       .then(() => {
@@ -476,6 +481,25 @@ export function ngcLoader(this: LoaderContext & { _compilation: any }) {
         });
       })
       .then(() => {
+        if (source) {
+          // We need to validate diagnostics. We ignore type checking though, to save time.
+          const diagnostics = refactor.getDiagnostics(false);
+          if (diagnostics.length) {
+            let message = '';
+
+            diagnostics.forEach(diagnostic => {
+              const position = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start);
+
+              const fileName = diagnostic.file.fileName;
+              const {line, character} = position;
+
+              const messageText = ts.flattenDiagnosticMessageText(diagnostic.messageText, '\n');
+              message += `${fileName} (${line + 1},${character + 1}): ${messageText}\n`;
+            });
+            throw new Error(message);
+          }
+        }
+
         // Force a few compiler options to make sure we get the result we want.
         const compilerOptions: ts.CompilerOptions = Object.assign({}, plugin.compilerOptions, {
           inlineSources: true,

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

@@ -38,14 +38,19 @@ export class TypeScriptFileRefactor {
 
   constructor(fileName: string,
               _host: ts.CompilerHost,
-              private _program?: ts.Program) {
+              private _program?: ts.Program,
+              source?: string | null) {
     fileName = resolve(fileName, _host, _program).replace(/\\/g, '/');
     this._fileName = fileName;
     if (_program) {
-      this._sourceFile = _program.getSourceFile(fileName);
+      if (source) {
+        this._sourceFile = ts.createSourceFile(fileName, source, ts.ScriptTarget.Latest, true);
+      } else {
+        this._sourceFile = _program.getSourceFile(fileName);
+      }
     }
     if (!this._sourceFile) {
-      this._sourceFile = ts.createSourceFile(fileName, _host.readFile(fileName),
+      this._sourceFile = ts.createSourceFile(fileName, source || _host.readFile(fileName),
         ts.ScriptTarget.Latest, true);
     }
     this._sourceText = this._sourceFile.getFullText(this._sourceFile);
@@ -55,7 +60,7 @@ export class TypeScriptFileRefactor {
   /**
    * Collates the diagnostic messages for the current source file
    */
-  getDiagnostics(): ts.Diagnostic[] {
+  getDiagnostics(typeCheck = true): ts.Diagnostic[] {
     if (!this._program) {
       return [];
     }
@@ -66,7 +71,7 @@ export class TypeScriptFileRefactor {
     }
     diagnostics = diagnostics.concat(
       this._program.getSyntacticDiagnostics(this._sourceFile),
-      this._program.getSemanticDiagnostics(this._sourceFile));
+      typeCheck ? this._program.getSemanticDiagnostics(this._sourceFile) : []);
 
     return diagnostics;
   }

tests/e2e/assets/webpack/test-app-weird/not/so/source/app/app.component.html

@@ -3,3 +3,11 @@ <h1>hello world</h1>
   <a [routerLink]="['lazy']">lazy</a>
   <router-outlet></router-outlet>
 </div>
+
+<!-- @ifdef DEBUG -->
+<p>DEBUG_ONLY</p>
+<!-- @endif -->
+
+<!-- @ifndef DEBUG -->
+<p>PRODUCTION_ONLY</p>
+<!-- @endif -->

tests/e2e/assets/webpack/test-app-weird/not/so/source/app/app.component.scss

@@ -1,3 +1,15 @@
 :host {
   background-color: blue;
 }
+
+// @ifdef DEBUG
+:host::before {
+  content: 'DEBUG_ONLY';
+}
+// @endif
+
+// @ifndef DEBUG
+:host::before {
+  content: 'PRODUCTION_ONLY';
+}
+// @endif

tests/e2e/assets/webpack/test-app-weird/not/so/source/app/app.module.ts

@@ -10,6 +10,15 @@ import { AppComponent } from './app.component';
 export class HomeView {}
 
 
+// @ifdef DEBUG
+console.log("DEBUG_ONLY");
+// @endif
+
+// @ifndef DEBUG
+console.log("PRODUCTION_ONLY");
+// @endif
+
+
 @NgModule({
   declarations: [
     AppComponent,

tests/e2e/assets/webpack/test-app-weird/package.json

@@ -19,6 +19,7 @@
   "devDependencies": {
     "node-sass": "^3.7.0",
     "performance-now": "^0.2.0",
+    "preprocess-loader": "^0.2.2",
     "raw-loader": "^0.5.1",
     "sass-loader": "^3.2.0",
     "typescript": "~2.1.0",

tests/e2e/assets/webpack/test-app-weird/webpack.config.js

@@ -1,5 +1,10 @@
 const ngToolsWebpack = require('@ngtools/webpack');
 
+const flags = require('./webpack.flags.json');
+
+const preprocessLoader = 'preprocess-loader' + (flags.DEBUG ? '?+DEBUG' : '');
+
+
 module.exports = {
   resolve: {
     extensions: ['.ts', '.js']
@@ -15,10 +20,14 @@ module.exports = {
   ],
   module: {
     loaders: [
-      { test: /\.scss$/, loaders: ['raw-loader', 'sass-loader'] },
+      { test: /\.scss$/, loaders: ['raw-loader', 'sass-loader', preprocessLoader] },
       { test: /\.css$/, loader: 'raw-loader' },
-      { test: /\.html$/, loader: 'raw-loader' },
-      { test: /\.ts$/, loader: '@ngtools/webpack' }
+      { test: /\.html$/, loaders: ['raw-loader', preprocessLoader] },
+      // Use preprocess to remove DEBUG only code.
+      { test: /\.ts$/, use: [
+        { loader: '@ngtools/webpack' },
+        { loader: preprocessLoader }
+      ] }
     ]
   },
   devServer: {

tests/e2e/assets/webpack/test-app-weird/webpack.flags.json

@@ -0,0 +1,3 @@
+{
+  "DEBUG": false
+}

tests/e2e/tests/packages/webpack/weird.ts

@@ -1,9 +1,9 @@
 import {normalize} from 'path';
 
 import {createProjectFromAsset} from '../../../utils/assets';
-import {exec} from '../../../utils/process';
+import {exec, execWithEnv} from '../../../utils/process';
 import {updateJsonFile} from '../../../utils/project';
-import {expectFileSizeToBeUnder, expectFileToExist} from '../../../utils/fs';
+import {expectFileSizeToBeUnder, expectFileToExist, expectFileToMatch} from '../../../utils/fs';
 import {expectToFail} from '../../../utils/utils';
 
 
@@ -18,16 +18,28 @@ export default function(skipCleaning: () => void) {
     .then(() => expectFileSizeToBeUnder('dist/app.main.js', 410000))
     .then(() => expectFileSizeToBeUnder('dist/0.app.main.js', 40000))
 
+    // Verify that we're using the production environment.
+    .then(() => expectFileToMatch('dist/app.main.js', /PRODUCTION_ONLY/))
+    .then(() => expectToFail(() => expectFileToMatch('dist/app.main.js', /DEBUG_ONLY/)))
+
     // Skip code generation and rebuild.
     .then(() => updateJsonFile('aotplugin.config.json', json => {
       json['skipCodeGeneration'] = true;
     }))
+    .then(() => updateJsonFile('webpack.flags.json', json => {
+      json['DEBUG'] = true;
+    }))
     .then(() => exec(normalize('node_modules/.bin/webpack'), '-p'))
     .then(() => expectFileToExist('dist/app.main.js'))
     .then(() => expectFileToExist('dist/0.app.main.js'))
     .then(() => expectFileToExist('dist/1.app.main.js'))
     .then(() => expectFileToExist('dist/2.app.main.js'))
     .then(() => expectToFail(() => expectFileSizeToBeUnder('dist/app.main.js', 410000)))
     .then(() => expectFileSizeToBeUnder('dist/0.app.main.js', 40000))
+
+    // Verify that we're using the debug environment now.
+    .then(() => expectFileToMatch('dist/app.main.js', /DEBUG_ONLY/))
+    .then(() => expectToFail(() => expectFileToMatch('dist/app.main.js', /PRODUCTION_ONLY/)))
+
     .then(() => skipCleaning());
 }