fix(@ngtools/webpack): avoid caching binary resources as UTF8

Author: clydin

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

@@ -97,7 +97,6 @@ export class WebpackCompilerHost implements ts.CompilerHost {
   private _delegate: ts.CompilerHost;
   private _files: {[path: string]: VirtualFileStats | null} = Object.create(null);
   private _directories: {[path: string]: VirtualDirStats | null} = Object.create(null);
-  private _cachedResources: {[path: string]: string | undefined} = Object.create(null);
 
   private _changedFiles: {[path: string]: boolean} = Object.create(null);
   private _changedDirs: {[path: string]: boolean} = Object.create(null);
@@ -174,8 +173,8 @@ export class WebpackCompilerHost implements ts.CompilerHost {
     fileName = this.resolve(fileName);
     if (fileName in this._files) {
       this._files[fileName] = null;
-      this._changedFiles[fileName] = true;
     }
+    this._changedFiles[fileName] = true;
   }
 
   fileExists(fileName: string, delegate = true): boolean {
@@ -299,22 +298,7 @@ export class WebpackCompilerHost implements ts.CompilerHost {
     if (this._resourceLoader) {
       // These paths are meant to be used by the loader so we must denormalize them.
       const denormalizedFileName = this.denormalizePath(fileName);
-      const resourceDeps = this._resourceLoader.getResourceDependencies(denormalizedFileName);
-
-      if (this._cachedResources[fileName] === undefined
-        || resourceDeps.some((dep) => this._changedFiles[this.resolve(dep)])) {
-        return this._resourceLoader.get(denormalizedFileName)
-          .then((resource) => {
-            // Add resource dependencies to the compiler host file list.
-            // This way we can check the changed files list to determine whether to use cache.
-            this._resourceLoader.getResourceDependencies(denormalizedFileName)
-              .forEach((dep) => this.readFile(dep));
-            this._cachedResources[fileName] = resource;
-            return resource;
-          });
-      } else {
-        return this._cachedResources[fileName];
-      }
+      return this._resourceLoader.get(denormalizedFileName);
     } else {
       return this.readFile(fileName);
     }

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

@@ -18,6 +18,7 @@ export class WebpackResourceLoader {
   private _context: string;
   private _uniqueId = 0;
   private _resourceDependencies = new Map<string, string[]>();
+  private _cachedResources = new Map<string, string>();
 
   constructor() {}
 
@@ -69,6 +70,11 @@ export class WebpackResourceLoader {
 
     childCompiler.plugin('this-compilation', (compilation: any) => {
       compilation.plugin('additional-assets', (callback: (err?: Error) => void) => {
+        if (this._cachedResources.has(compilation.fullHash)) {
+          callback();
+          return;
+        }
+
         const asset = compilation.assets[filePath];
         if (asset) {
           this._evaluate({ outputName: filePath, source: asset.source() })
@@ -104,12 +110,17 @@ export class WebpackResourceLoader {
           // Save the dependencies for this resource.
           this._resourceDependencies.set(filePath, childCompilation.fileDependencies);
 
-          resolve({
-            // Output name.
-            outputName: filePath,
-            // Compiled code.
-            source: childCompilation.assets[filePath].source()
-          });
+          const compilationHash = childCompilation.fullHash;
+          if (this._cachedResources.has(compilationHash)) {
+            resolve({
+              outputName: filePath,
+              source: this._cachedResources.get(compilationHash),
+            });
+          } else {
+            const source = childCompilation.assets[filePath].source();
+            this._cachedResources.set(compilationHash, source);
+            resolve({ outputName: filePath, source });
+          }
         }
       });
     });