refactor(@angular/cli): use memory FS for i18n extraction (#6306)

Author: clydin

package.json

@@ -70,6 +70,7 @@
     "loader-utils": "^1.0.2",
     "lodash": "^4.11.1",
     "magic-string": "^0.19.0",
+    "memory-fs": "^0.4.1",
     "minimatch": "^3.0.3",
     "node-modules-path": "^1.0.0",
     "nopt": "^4.0.1",

packages/@angular/cli/package.json

@@ -55,6 +55,7 @@
     "less": "^2.7.2",
     "less-loader": "^4.0.2",
     "lodash": "^4.11.1",
+    "memory-fs": "^0.4.1",
     "minimatch": "^3.0.3",
     "node-modules-path": "^1.0.0",
     "nopt": "^4.0.1",

packages/@angular/cli/tasks/extract-i18n.ts

@@ -1,25 +1,18 @@
 import * as webpack from 'webpack';
-import * as path from 'path';
-import * as rimraf from 'rimraf';
+import { XI18nWebpackConfig } from '../models/webpack-xi18n-config';
+import { getAppFromConfig } from '../utilities/app-utils';
 
 const Task = require('../ember-cli/lib/models/task');
+const MemoryFS = require('memory-fs');
 
-import {XI18nWebpackConfig} from '../models/webpack-xi18n-config';
-import {getAppFromConfig} from '../utilities/app-utils';
 
 export const Extracti18nTask = Task.extend({
   run: function (runTaskOptions: any) {
-
-    const project = this.project;
-
     const appConfig = getAppFromConfig(runTaskOptions.app);
 
-    const buildDir = '.tmp';
-    const genDir = runTaskOptions.outputPath || appConfig.root;
-
     const config = new XI18nWebpackConfig({
-      genDir,
-      buildDir,
+      genDir: runTaskOptions.outputPath || appConfig.root,
+      buildDir: '.tmp',
       i18nFormat: runTaskOptions.i18nFormat,
       locale: runTaskOptions.locale,
       outFile: runTaskOptions.outFile,
@@ -29,6 +22,7 @@ export const Extracti18nTask = Task.extend({
     }, appConfig).buildConfig();
 
     const webpackCompiler = webpack(config);
+    webpackCompiler.outputFileSystem = new MemoryFS();
 
     return new Promise((resolve, reject) => {
       const callback: webpack.compiler.CompilerCallback = (err, stats) => {
@@ -45,15 +39,11 @@ export const Extracti18nTask = Task.extend({
 
       webpackCompiler.run(callback);
     })
-      .then(() => {
-        // Deletes temporary build folder
-        rimraf.sync(path.resolve(project.root, buildDir));
-      })
-      .catch((err: Error) => {
-        if (err) {
-          this.ui.writeError('\nAn error occured during the i18n extraction:\n'
-            + ((err && err.stack) || err));
-        }
-      });
+    .catch((err: Error) => {
+      if (err) {
+        this.ui.writeError('\nAn error occured during the i18n extraction:\n'
+          + ((err && err.stack) || err));
+      }
+    });
   }
 });