refactor(@angular-devkit/build-angular): remove jest-worker direct dependency

The worker pool for differential loading and i18n processing is now managed by the `piscina` dependency. This dependency is already used within the recently added JavaScript optimizer refactoring and reduces both the number of direct dependencies and amount of code to setup the worker pools.

Author: clydin

package.json

@@ -166,7 +166,6 @@
     "jasmine": "^3.3.1",
     "jasmine-core": "~3.7.0",
     "jasmine-spec-reporter": "~7.0.0",
-    "jest-worker": "27.0.2",
     "jquery": "^3.3.1",
     "jsonc-parser": "3.0.0",
     "karma": "~6.3.0",

packages/angular_devkit/build_angular/BUILD.bazel

@@ -154,7 +154,6 @@ ts_library(
         "@npm//glob",
         "@npm//https-proxy-agent",
         "@npm//inquirer",
-        "@npm//jest-worker",
         "@npm//karma",
         "@npm//karma-source-map-support",
         "@npm//less",

packages/angular_devkit/build_angular/package.json

@@ -38,7 +38,6 @@
     "glob": "7.1.7",
     "https-proxy-agent": "5.0.0",
     "inquirer": "8.1.1",
-    "jest-worker": "27.0.2",
     "karma-source-map-support": "1.4.0",
     "less": "4.1.1",
     "less-loader": "10.0.0",

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

@@ -6,73 +6,40 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import { Worker as JestWorker } from 'jest-worker';
-import * as os from 'os';
-import * as path from 'path';
-import { serialize } from 'v8';
+import Piscina from 'piscina';
 import { BundleActionCache } from './action-cache';
 import { maxWorkers } from './environment-options';
 import { I18nOptions } from './i18n-options';
 import { InlineOptions, ProcessBundleOptions, ProcessBundleResult } from './process-bundle';
 
-let workerFile = require.resolve('./process-bundle');
-workerFile =
-  path.extname(workerFile) === '.ts' ? require.resolve('./process-bundle-bootstrap') : workerFile;
+const workerFile = require.resolve('./process-bundle');
 
 export class BundleActionExecutor {
-  private largeWorker?: JestWorker;
-  private smallWorker?: JestWorker;
+  private workerPool?: Piscina;
   private cache?: BundleActionCache;
 
   constructor(
     private workerOptions: { cachePath?: string; i18n: I18nOptions },
     integrityAlgorithm?: string,
-    private readonly sizeThreshold = 32 * 1024,
   ) {
     if (workerOptions.cachePath) {
       this.cache = new BundleActionCache(workerOptions.cachePath, integrityAlgorithm);
     }
   }
 
-  private static executeMethod<O>(worker: JestWorker, method: string, input: unknown): Promise<O> {
-    return (worker as unknown as Record<string, (i: unknown) => Promise<O>>)[method](input);
-  }
-
-  private ensureLarge(): JestWorker {
-    if (this.largeWorker) {
-      return this.largeWorker;
-    }
-
-    // larger files are processed in a separate process to limit memory usage in the main process
-    return (this.largeWorker = new JestWorker(workerFile, {
-      exposedMethods: ['process', 'inlineLocales'],
-      setupArgs: [[...serialize(this.workerOptions)]],
-      numWorkers: maxWorkers,
-    }));
-  }
-
-  private ensureSmall(): JestWorker {
-    if (this.smallWorker) {
-      return this.smallWorker;
+  private ensureWorkerPool(): Piscina {
+    if (this.workerPool) {
+      return this.workerPool;
     }
 
-    // small files are processed in a limited number of threads to improve speed
-    // The limited number also prevents a large increase in memory usage for an otherwise short operation
-    return (this.smallWorker = new JestWorker(workerFile, {
-      exposedMethods: ['process', 'inlineLocales'],
-      setupArgs: [this.workerOptions],
-      numWorkers: os.cpus().length < 2 ? 1 : 2,
-      enableWorkerThreads: true,
-    }));
-  }
+    this.workerPool = new Piscina({
+      filename: workerFile,
+      name: 'process',
+      workerData: this.workerOptions,
+      maxThreads: maxWorkers,
+    });
 
-  private executeAction<O>(method: string, action: { code: string }): Promise<O> {
-    // code.length is not an exact byte count but close enough for this
-    if (action.code.length > this.sizeThreshold) {
-      return BundleActionExecutor.executeMethod<O>(this.ensureLarge(), method, action);
-    } else {
-      return BundleActionExecutor.executeMethod<O>(this.ensureSmall(), method, action);
-    }
+    return this.workerPool;
   }
 
   async process(action: ProcessBundleOptions): Promise<ProcessBundleResult> {
@@ -89,7 +56,7 @@ export class BundleActionExecutor {
       } catch {}
     }
 
-    return this.executeAction<ProcessBundleResult>('process', action);
+    return this.ensureWorkerPool().run(action, { name: 'process' });
   }
 
   processAll(actions: Iterable<ProcessBundleOptions>): AsyncIterable<ProcessBundleResult> {
@@ -99,7 +66,7 @@ export class BundleActionExecutor {
   async inline(
     action: InlineOptions,
   ): Promise<{ file: string; diagnostics: { type: string; message: string }[]; count: number }> {
-    return this.executeAction('inlineLocales', action);
+    return this.ensureWorkerPool().run(action, { name: 'inlineLocales' });
   }
 
   inlineAll(actions: Iterable<InlineOptions>) {
@@ -129,15 +96,6 @@ export class BundleActionExecutor {
   }
 
   stop(): void {
-    // Floating promises are intentional here
-    // https://github.com/facebook/jest/tree/56079a5aceacf32333089cea50c64385885fee26/packages/jest-worker#end
-    if (this.largeWorker) {
-      // eslint-disable-next-line @typescript-eslint/no-floating-promises
-      this.largeWorker.end();
-    }
-    if (this.smallWorker) {
-      // eslint-disable-next-line @typescript-eslint/no-floating-promises
-      this.smallWorker.end();
-    }
+    void this.workerPool?.destroy();
   }
 }

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

@@ -23,8 +23,8 @@ import * as fs from 'fs';
 import * as path from 'path';
 import { RawSourceMap, SourceMapConsumer, SourceMapGenerator } from 'source-map';
 import { minify } from 'terser';
-import * as v8 from 'v8';
 import { sources } from 'webpack';
+import { workerData } from 'worker_threads';
 import { allowMangle, allowMinify, shouldBeautify } from './environment-options';
 import { I18nOptions } from './i18n-options';
 
@@ -78,16 +78,7 @@ export const enum CacheKey {
   DownlevelMap = 3,
 }
 
-let cachePath: string | undefined;
-let i18n: I18nOptions | undefined;
-
-export function setup(data: number[] | { cachePath: string; i18n: I18nOptions }): void {
-  const options = Array.isArray(data)
-    ? (v8.deserialize(Buffer.from(data)) as { cachePath: string; i18n: I18nOptions })
-    : data;
-  cachePath = options.cachePath;
-  i18n = options.i18n;
-}
+const { cachePath, i18n } = (workerData || {}) as { cachePath?: string; i18n?: I18nOptions };
 
 async function cachePut(
   content: string,
@@ -413,7 +404,7 @@ async function terserMangle(
       code,
       options.map,
       outputCode,
-      (minifyOutput.map as unknown) as RawSourceMap,
+      minifyOutput.map as unknown as RawSourceMap,
       options.filename || '0',
       code.length > FAST_SOURCEMAP_THRESHOLD,
     );

yarn.lock

@@ -6694,7 +6694,7 @@ jasminewd2@^2.1.0:
   resolved "https://registry.yarnpkg.com/jasminewd2/-/jasminewd2-2.2.0.tgz#e37cf0b17f199cce23bea71b2039395246b4ec4e"
   integrity sha1-43zwsX8ZnM4jvqcbIDk5Uka07E4=
 
-jest-worker@27.0.2, jest-worker@^27.0.2:
+jest-worker@^27.0.2:
   version "27.0.2"
   resolved "https://registry.yarnpkg.com/jest-worker/-/jest-worker-27.0.2.tgz#4ebeb56cef48b3e7514552f80d0d80c0129f0b05"
   integrity sha512-EoBdilOTTyOgmHXtw/cPc+ZrCA0KJMrkXzkrPGNwLmnvvlN1nj7MPrxpT7m+otSv2e1TLaVffzDnE/LB14zJMg==