fix(@angular-devkit/build-angular): avoid extra filesystem access with i18n and differential loading

packages/angular_devkit/build_angular/src/browser/index.ts

@@ -365,7 +365,7 @@ export function buildWebpackBrowser(
                   if (actionOptions.sourceMaps) {
                     try {
                       map = fs.readFileSync(filename + '.map', 'utf8');
-                      if (es5Polyfills) {
+                      if (es5Polyfills || i18n.shouldInline) {
                         fs.unlinkSync(filename + '.map');
                       }
                     } catch {}
@@ -374,6 +374,10 @@ export function buildWebpackBrowser(
                   if (es5Polyfills) {
                     fs.unlinkSync(filename);
                     filename = filename.replace(/\-es20\d{2}/, '');
+                  } else if (i18n.shouldInline) {
+                    // Original files must be deleted with i18n to avoid the original files from
+                    // being copied over the translated files when copying the project assets.
+                    fs.unlinkSync(filename);
                   }
 
                   const es2015Polyfills = file.file.startsWith('polyfills-es20');
@@ -391,6 +395,8 @@ export function buildWebpackBrowser(
                     runtime: file.file.startsWith('runtime'),
                     ignoreOriginal: es5Polyfills,
                     optimizeOnly: es2015Polyfills,
+                    // When using i18n, file results are kept in memory for further processing
+                    memoryMode: i18n.shouldInline,
                   });
 
                   // ES2015 polyfills are only optimized; optimization check was performed above
@@ -451,41 +457,32 @@ export function buildWebpackBrowser(
                 if (i18n.shouldInline) {
                   spinner.start('Generating localized bundles...');
                   const inlineActions: InlineOptions[] = [];
-                  const processedFiles = new Set<string>();
                   for (const result of processResults) {
                     if (result.original) {
                       inlineActions.push({
                         filename: path.basename(result.original.filename),
-                        code: fs.readFileSync(result.original.filename, 'utf8'),
-                        map:
-                          result.original.map &&
-                          fs.readFileSync(result.original.map.filename, 'utf8'),
+                        // Memory mode is always enabled for i18n
+                        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+                        code: result.original.content!,
+                        map: result.original.map?.content,
                         outputPath: baseOutputPath,
                         es5: false,
                         missingTranslation: options.i18nMissingTranslation,
                         setLocale: result.name === mainChunkId,
                       });
-                      processedFiles.add(result.original.filename);
-                      if (result.original.map) {
-                        processedFiles.add(result.original.map.filename);
-                      }
                     }
                     if (result.downlevel) {
                       inlineActions.push({
                         filename: path.basename(result.downlevel.filename),
-                        code: fs.readFileSync(result.downlevel.filename, 'utf8'),
-                        map:
-                          result.downlevel.map &&
-                          fs.readFileSync(result.downlevel.map.filename, 'utf8'),
+                        // Memory mode is always enabled for i18n
+                        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+                        code: result.downlevel.content!,
+                        map: result.downlevel.map?.content,
                         outputPath: baseOutputPath,
                         es5: true,
                         missingTranslation: options.i18nMissingTranslation,
                         setLocale: result.name === mainChunkId,
                       });
-                      processedFiles.add(result.downlevel.filename);
-                      if (result.downlevel.map) {
-                        processedFiles.add(result.downlevel.map.filename);
-                      }
                     }
                   }
 
@@ -520,9 +517,6 @@ export function buildWebpackBrowser(
                           glob: '**/*',
                           input: webpackOutputPath,
                           output: '',
-                          ignore: [...processedFiles].map((f) =>
-                            path.relative(webpackOutputPath, f),
-                          ),
                         },
                       ],
                       Array.from(outputPaths.values()),

packages/angular_devkit/build_angular/src/utils/action-executor.ts

@@ -77,21 +77,19 @@ export class BundleActionExecutor {
     actions: Iterable<I>,
     executor: (action: I) => Promise<O>,
   ): AsyncIterable<O> {
-    const executions = new Map<Promise<O>, Promise<O>>();
+    const executions = new Map<Promise<O>, Promise<[Promise<O>, O]>>();
     for (const action of actions) {
       const execution = executor(action);
       executions.set(
         execution,
-        execution.then((result) => {
-          executions.delete(execution);
-
-          return result;
-        }),
+        execution.then((result) => [execution, result]),
       );
     }
 
     while (executions.size > 0) {
-      yield Promise.race(executions.values());
+      const [execution, result] = await Promise.race(executions.values());
+      executions.delete(execution);
+      yield result;
     }
   }
 

packages/angular_devkit/build_angular/src/utils/process-bundle.ts

@@ -56,6 +56,7 @@ export interface ProcessBundleOptions {
   runtimeData?: ProcessBundleResult[];
   replacements?: [string, string][];
   supportedBrowsers?: string[] | Record<string, string>;
+  memoryMode?: boolean;
 }
 
 export interface ProcessBundleResult {
@@ -69,9 +70,11 @@ export interface ProcessBundleFile {
   filename: string;
   size: number;
   integrity?: string;
+  content?: string;
   map?: {
     filename: string;
     size: number;
+    content?: string;
   };
 }
 
@@ -200,6 +203,7 @@ async function processBundle(
     hiddenSourceMaps,
     cacheKeys = [],
     integrityAlgorithm,
+    memoryMode,
   } = options;
 
   const filename = path.basename(filepath);
@@ -242,17 +246,27 @@ async function processBundle(
       mapContent,
       cacheKeys[isOriginal ? CacheKey.OriginalMap : CacheKey.DownlevelMap],
     );
-    fs.writeFileSync(filepath + '.map', mapContent);
+    if (!memoryMode) {
+      fs.writeFileSync(filepath + '.map', mapContent);
+    }
   }
 
-  const fileResult = createFileEntry(filepath, resultCode, mapContent, integrityAlgorithm);
+  const fileResult = createFileEntry(
+    filepath,
+    resultCode,
+    mapContent,
+    memoryMode,
+    integrityAlgorithm,
+  );
 
   await cachePut(
     resultCode,
     cacheKeys[isOriginal ? CacheKey.OriginalCode : CacheKey.DownlevelCode],
     fileResult.integrity,
   );
-  fs.writeFileSync(filepath, resultCode);
+  if (!memoryMode) {
+    fs.writeFileSync(filepath, resultCode);
+  }
 
   return fileResult;
 }
@@ -293,17 +307,20 @@ function createFileEntry(
   filename: string,
   code: string,
   map: string | undefined,
+  memoryMode?: boolean,
   integrityAlgorithm?: string,
 ): ProcessBundleFile {
   return {
     filename: filename,
     size: Buffer.byteLength(code),
     integrity: integrityAlgorithm && generateIntegrityValue(integrityAlgorithm, code),
+    content: memoryMode ? code : undefined,
     map: !map
       ? undefined
       : {
           filename: filename + '.map',
           size: Buffer.byteLength(map),
+          content: memoryMode ? map : undefined,
         },
   };
 }