node-threads-pool/lib/adam.js

Node-Threads-Pool is a tool for creating thread pools in Node.js, making it easy to implement efficient parallel computing. With Node-Threads-Pool, you can easily create and manage multiple threads, allocate tasks to worker threads in the thread pool, and

const {Worker} = require("worker_threads");
module.exports = class {
  constructor(max = 1) {
    this._max = max;
    this._queue = [];
    this._workers = new Set();
  };

  async createWorker(filename, options, resolve, reject) {
    const self = this;
    const {_queue, _workers} = this;
    const worker = new Worker(filename, options);
    worker.on("message", message => {
      resolve(message);
      worker.terminate();
    });
    worker.on("error", error => {
      resolve(error);
      worker.terminate();
    });
    worker.on("exit", code => {
      _workers.delete(worker);
      if(_queue.length > 0) {
        const {filename, options, resolve, reject} = _queue.splice(0, 1)[0];
        self.createWorker(filename, options, resolve, reject);
      }
      if(code !== 0) {
        reject(new Error(`thread error. code: ${code}`));
      }
    });
    _workers.add(worker);
  }

  async run(filename, options) {
    const self = this;
    const {_workers, _queue, _max} = this;
    return new Promise((resolve, reject) => {
      if(_workers.size < _max) {
        self.createWorker(filename, options, resolve, reject);
      } else {
        _queue.push({
          filename, 
          options,
          resolve,
          reject
        });
      }
    });
  }    
}