js 栈异步队列

class AsyncQueue {
  constructor(concurrency = 1) {
    this.concurrency = concurrency;
    this.queue = [];
    this.running = 0;
  }

  pushTask(task) {
    this.queue.push(task);
    this.next();
  }

  async next() {
    while (this.running < this.concurrency && this.queue.length) {
      const task = this.queue.shift();
      this.running++;
      task().finally(() => {
        this.running--;
        this.next();
      });
    }
  }
}

// 使用示例
const queue = new AsyncQueue(2); // 设置并发数为2

const createTask = (i) => () => new Promise((resolve) => {
  setTimeout(() => {
    console.log(`Task ${i} done`);
    resolve();
  }, 1000);
});

queue.pushTask(createTask(1));
queue.pushTask(createTask(2));
queue.pushTask(createTask(3));
queue.pushTask(createTask(4));