fix(@angular-devkit/build-optimizer): support disabled webpack cache (#138)

Fix #136

Author: actra-gschuster

package.json

@@ -52,6 +52,7 @@
     "@types/semver": "^5.3.30",
     "@types/source-map": "^0.5.0",
     "@types/webpack": "^3.0.2",
+    "@types/webpack-sources": "^0.1.3",
     "common-tags": "^1.3.1",
     "conventional-changelog": "^1.1.0",
     "glob": "^7.0.3",
@@ -71,7 +72,8 @@
     "ts-node": "^2.0.0",
     "tslint": "^5.5.0",
     "typescript": "~2.3.0",
-    "v8-profiler": "^5.7.0"
+    "v8-profiler": "^5.7.0",
+    "webpack-sources": "^1.0.1"
   },
   "devDependencies": {
     "protobufjs": "5.0.0"

packages/angular_devkit/build_optimizer/package.json

@@ -11,6 +11,7 @@
   "dependencies": {
     "loader-utils": "^1.1.0",
     "source-map": "^0.5.6",
-    "typescript": "^2.3.3"
+    "typescript": "^2.3.3",
+    "webpack-sources": "^1.0.1"
   }
 }

packages/angular_devkit/build_optimizer/src/purify/webpack-plugin.ts

@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import * as webpack from 'webpack';
+import { ConcatSource, RawSource } from 'webpack-sources';
 import { purify } from './purify';
 
 
@@ -23,9 +24,8 @@ export class PurifyPlugin {
           chunk.files
             .filter((fileName: string) => fileName.endsWith('.js'))
             .forEach((fileName: string) => {
-              const purifiedSource = purify(compilation.assets[fileName].source());
-              compilation.assets[fileName]._cachedSource = purifiedSource;
-              compilation.assets[fileName]._source.source = () => purifiedSource;
+              const purified: string = purify(compilation.assets[fileName].source());
+              compilation.assets[fileName] = new ConcatSource(new RawSource(purified));
             });
         });
         callback();