使用promises构建一个请求队列？

class RequestQueue {
  constructor() {
    this.queue = [];
    this.isProcessing = false;
  }

  addRequest(request) {
    const promise = new Promise((resolve, reject) => {
      const requestWithCallback = () => {
        request()
          .then(resolve)
          .catch(reject)
          .finally(() => {
            this.processNextRequest();
          });
      };

      if (this.isProcessing) {
        this.queue.push(requestWithCallback);
      } else {
        this.isProcessing = true;
        requestWithCallback();
      }
    });

    return promise;
  }

  processNextRequest() {
    if (this.queue.length > 0) {
      const nextRequest = this.queue.shift();
      nextRequest();
    } else {
      this.isProcessing = false;
    }
  }
}

const queue = new RequestQueue();

const request1 = () => {
  return new Promise((resolve, reject) => {
    // 执行请求1的逻辑
    resolve('请求1完成');
  });
};

const request2 = () => {
  return new Promise((resolve, reject) => {
    // 执行请求2的逻辑
    resolve('请求2完成');
  });
};

const request3 = () => {
  return new Promise((resolve, reject) => {
    // 执行请求3的逻辑
    resolve('请求3完成');
  });
};

queue.addRequest(request1)
  .then(result => {
    console.log(result);
    return queue.addRequest(request2);
  })
  .then(result => {
    console.log(result);
    return queue.addRequest(request3);
  })
  .then(result => {
    console.log(result);
  })
  .catch(error => {
    console.error(error);
  });