模拟Promise，但在代码块中运行实际代码

class MyPromise {
  constructor(executor) {
    this.status = 'pending'; // 初始状态为pending
    this.value = undefined; // 异步操作成功的结果
    this.reason = undefined; // 异步操作失败的原因

    const resolve = (value) => {
      if (this.status === 'pending') {
        this.status = 'fulfilled'; // 将状态设置为fulfilled
        this.value = value; // 保存异步操作成功的结果
      }
    };

    const reject = (reason) => {
      if (this.status === 'pending') {
        this.status = 'rejected'; // 将状态设置为rejected
        this.reason = reason; // 保存异步操作失败的原因
      }
    };

    try {
      executor(resolve, reject); // 执行执行器函数，并传入resolve和reject函数
    } catch (error) {
      reject(error); // 如果执行器函数抛出异常，则将状态设置为rejected
    }
  }

  then(onFulfilled, onRejected) {
    if (this.status === 'fulfilled') {
      onFulfilled(this.value); // 如果状态为fulfilled，则调用onFulfilled回调函数
    } else if (this.status === 'rejected') {
      onRejected(this.reason); // 如果状态为rejected，则调用onRejected回调函数
    }
  }
}