worker-pool.ts

/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.dev/license
 */

import { getCompileCacheDir } from 'node:module';
import { Piscina } from 'piscina';

export type WorkerPoolOptions = ConstructorParameters<typeof Piscina>[0];

export class WorkerPool extends Piscina {
  constructor(options: WorkerPoolOptions) {
    const piscinaOptions: WorkerPoolOptions = {
      minThreads: 1,
      idleTimeout: 1000,
      // Web containers do not support transferable objects with receiveOnMessagePort which
      // is used when the Atomics based wait loop is enable.
      useAtomics: !process.versions.webcontainer,
      recordTiming: false,
      ...options,
    };

    // Enable compile code caching if enabled for the main process (only exists on Node.js v22.8+).
    // Skip if running inside Bazel via a RUNFILES environment variable check. The cache does not work
    // well with Bazel's hermeticity requirements.
    const compileCacheDirectory = process.env['RUNFILES'] ? undefined : getCompileCacheDir?.();
    if (compileCacheDirectory) {
      if (typeof piscinaOptions.env === 'object') {
        piscinaOptions.env['NODE_COMPILE_CACHE'] = compileCacheDirectory;
      } else {
        // Default behavior of `env` option is to copy current process values
        piscinaOptions.env = {
          ...process.env,
          'NODE_COMPILE_CACHE': compileCacheDirectory,
        };
      }
    }

    super(piscinaOptions);
  }
}