refactor(@angular/build): improve BuildOutputFile property access

The `BuildOutputFile` type's helper functions have been adjusted to cache
commonly accessed property values to avoid potentially expensive repeat
processing. This includes encoding/decoding UTF-8 content and calculating
hash values for the output file content. A size property has also been
added to allow consumers to more directly determine the byte size of the
output file. The size property is currently unused but will be leveraged
in forthcoming updates to bundle budgets and console info logging.

Author: clydin

goldens/public-api/angular/build/index.api.md

@@ -91,6 +91,8 @@ export interface BuildOutputFile extends OutputFile {
     // (undocumented)
     clone: () => BuildOutputFile;
     // (undocumented)
+    readonly size: number;
+    // (undocumented)
     type: BuildOutputFileType;
 }
 

packages/angular/build/src/builders/application/execute-post-bundle.ts

@@ -14,7 +14,7 @@ import {
 } from '../../tools/esbuild/bundler-context';
 import { BuildOutputAsset } from '../../tools/esbuild/bundler-execution-result';
 import { generateIndexHtml } from '../../tools/esbuild/index-html-generator';
-import { createOutputFileFromText } from '../../tools/esbuild/utils';
+import { createOutputFile } from '../../tools/esbuild/utils';
 import { maxWorkers } from '../../utils/environment-options';
 import { prerenderPages } from '../../utils/server-rendering/prerender';
 import { augmentAppWithServiceWorkerEsbuild } from '../../utils/service-worker';
@@ -84,14 +84,14 @@ export async function executePostBundleSteps(
 
     additionalHtmlOutputFiles.set(
       indexHtmlOptions.output,
-      createOutputFileFromText(indexHtmlOptions.output, csrContent, BuildOutputFileType.Browser),
+      createOutputFile(indexHtmlOptions.output, csrContent, BuildOutputFileType.Browser),
     );
 
     if (ssrContent) {
       const serverIndexHtmlFilename = 'index.server.html';
       additionalHtmlOutputFiles.set(
         serverIndexHtmlFilename,
-        createOutputFileFromText(serverIndexHtmlFilename, ssrContent, BuildOutputFileType.Server),
+        createOutputFile(serverIndexHtmlFilename, ssrContent, BuildOutputFileType.Server),
       );
 
       ssrIndexContent = ssrContent;
@@ -131,7 +131,7 @@ export async function executePostBundleSteps(
     for (const [path, content] of Object.entries(output)) {
       additionalHtmlOutputFiles.set(
         path,
-        createOutputFileFromText(path, content, BuildOutputFileType.Browser),
+        createOutputFile(path, content, BuildOutputFileType.Browser),
       );
     }
   }
@@ -153,11 +153,7 @@ export async function executePostBundleSteps(
       );
 
       additionalOutputFiles.push(
-        createOutputFileFromText(
-          'ngsw.json',
-          serviceWorkerResult.manifest,
-          BuildOutputFileType.Browser,
-        ),
+        createOutputFile('ngsw.json', serviceWorkerResult.manifest, BuildOutputFileType.Browser),
       );
       additionalAssets.push(...serviceWorkerResult.assetFiles);
     } catch (error) {

packages/angular/build/src/tools/esbuild/bundler-context.ts

@@ -55,6 +55,7 @@ export enum BuildOutputFileType {
 
 export interface BuildOutputFile extends OutputFile {
   type: BuildOutputFileType;
+  readonly size: number;
   clone: () => BuildOutputFile;
 }
 

packages/angular/build/src/tools/esbuild/bundler-execution-result.ts

@@ -11,7 +11,7 @@ import { normalize } from 'node:path';
 import type { ChangedFiles } from '../../tools/esbuild/watcher';
 import type { SourceFileCache } from './angular/source-file-cache';
 import type { BuildOutputFile, BuildOutputFileType, BundlerContext } from './bundler-context';
-import { createOutputFileFromText } from './utils';
+import { createOutputFile } from './utils';
 
 export interface BuildOutputAsset {
   source: string;
@@ -49,8 +49,8 @@ export class ExecutionResult {
     private codeBundleCache?: SourceFileCache,
   ) {}
 
-  addOutputFile(path: string, content: string, type: BuildOutputFileType): void {
-    this.outputFiles.push(createOutputFileFromText(path, content, type));
+  addOutputFile(path: string, content: string | Uint8Array, type: BuildOutputFileType): void {
+    this.outputFiles.push(createOutputFile(path, content, type));
   }
 
   addAssets(assets: BuildOutputAsset[]): void {

packages/angular/build/src/tools/esbuild/i18n-inliner.ts

@@ -9,7 +9,7 @@
 import assert from 'node:assert';
 import Piscina from 'piscina';
 import { BuildOutputFile, BuildOutputFileType } from './bundler-context';
-import { createOutputFileFromText } from './utils';
+import { createOutputFile } from './utils';
 
 /**
  * A keyword used to indicate if a JavaScript file may require inlining of translations.
@@ -139,9 +139,9 @@ export class I18nInliner {
         const type = this.#fileToType.get(file);
         assert(type !== undefined, 'localized file should always have a type' + file);
 
-        const resultFiles = [createOutputFileFromText(file, code, type)];
+        const resultFiles = [createOutputFile(file, code, type)];
         if (map) {
-          resultFiles.push(createOutputFileFromText(file + '.map', map, type));
+          resultFiles.push(createOutputFile(file + '.map', map, type));
         }
 
         for (const message of messages) {

packages/angular/build/src/tools/esbuild/utils.ts

@@ -294,64 +294,104 @@ export async function emitFilesToDisk<T = BuildOutputAsset | BuildOutputFile>(
   }
 }
 
-export function createOutputFileFromText(
+export function createOutputFile(
   path: string,
-  text: string,
+  data: string | Uint8Array,
   type: BuildOutputFileType,
 ): BuildOutputFile {
-  return {
-    path,
-    text,
-    type,
-    get hash() {
-      return createHash('sha256').update(this.text).digest('hex');
-    },
-    get contents() {
-      return Buffer.from(this.text, 'utf-8');
-    },
-    clone(): BuildOutputFile {
-      return createOutputFileFromText(this.path, this.text, this.type);
-    },
-  };
+  if (typeof data === 'string') {
+    let cachedContents: Uint8Array | null = null;
+    let cachedText: string | null = data;
+    let cachedHash: string | null = null;
+
+    return {
+      path,
+      type,
+      get contents(): Uint8Array {
+        cachedContents ??= new TextEncoder().encode(data);
+
+        return cachedContents;
+      },
+      set contents(value: Uint8Array) {
+        cachedContents = value;
+        cachedText = null;
+      },
+      get text(): string {
+        cachedText ??= new TextDecoder('utf-8').decode(this.contents);
+
+        return cachedText;
+      },
+      get size(): number {
+        return this.contents.byteLength;
+      },
+      get hash(): string {
+        cachedHash ??= createHash('sha256')
+          .update(cachedText ?? this.contents)
+          .digest('hex');
+
+        return cachedHash;
+      },
+      clone(): BuildOutputFile {
+        return createOutputFile(this.path, cachedText ?? this.contents, this.type);
+      },
+    };
+  } else {
+    let cachedContents = data;
+    let cachedText: string | null = null;
+    let cachedHash: string | null = null;
+
+    return {
+      get contents(): Uint8Array {
+        return cachedContents;
+      },
+      set contents(value: Uint8Array) {
+        cachedContents = value;
+        cachedText = null;
+      },
+      path,
+      type,
+      get size(): number {
+        return this.contents.byteLength;
+      },
+      get text(): string {
+        cachedText ??= new TextDecoder('utf-8').decode(this.contents);
+
+        return cachedText;
+      },
+      get hash(): string {
+        cachedHash ??= createHash('sha256').update(this.contents).digest('hex');
+
+        return cachedHash;
+      },
+      clone(): BuildOutputFile {
+        return createOutputFile(this.path, this.contents, this.type);
+      },
+    };
+  }
 }
 
-export function createOutputFileFromData(
-  path: string,
-  data: Uint8Array,
-  type: BuildOutputFileType,
-): BuildOutputFile {
+export function convertOutputFile(file: OutputFile, type: BuildOutputFileType): BuildOutputFile {
+  let { contents: cachedContents } = file;
+  let cachedText: string | null = null;
+
   return {
-    path,
-    type,
-    get text() {
-      return Buffer.from(data.buffer, data.byteOffset, data.byteLength).toString('utf-8');
+    get contents(): Uint8Array {
+      return cachedContents;
     },
-    get hash() {
-      return createHash('sha256').update(this.text).digest('hex');
+    set contents(value: Uint8Array) {
+      cachedContents = value;
+      cachedText = null;
     },
-    get contents() {
-      return data;
-    },
-    clone(): BuildOutputFile {
-      return createOutputFileFromData(this.path, this.contents, this.type);
+    hash: file.hash,
+    path: file.path,
+    type,
+    get size(): number {
+      return this.contents.byteLength;
     },
-  };
-}
-
-export function convertOutputFile(file: OutputFile, type: BuildOutputFileType): BuildOutputFile {
-  const { path, contents, hash } = file;
+    get text(): string {
+      cachedText ??= new TextDecoder('utf-8').decode(this.contents);
 
-  return {
-    contents,
-    hash,
-    path,
-    type,
-    get text() {
-      return Buffer.from(
-        this.contents.buffer,
-        this.contents.byteOffset,
-        this.contents.byteLength,
-      ).toString('utf-8');
+      return cachedText;
     },
     clone(): BuildOutputFile {
       return convertOutputFile(this, this.type);