如何订阅包含Promise的可观察对象链

// 创建可观察对象链
const observable1 = new Observable();
const observable2 = new Observable();
const observable3 = new Observable();

// 将可观察对象链转换为Promise链
const promise1 = new Promise((resolve, reject) => {
  observable1.subscribe(resolve);
});
const promise2 = new Promise((resolve, reject) => {
  observable2.subscribe(resolve);
});
const promise3 = new Promise((resolve, reject) => {
  observable3.subscribe(resolve);
});

// 订阅Promise链
promise1
  .then(value1 => {
    // 处理promise1的成功值
    console.log(value1);
    return promise2; // 返回下一个Promise链
  })
  .then(value2 => {
    // 处理promise2的成功值
    console.log(value2);
    return promise3; // 返回下一个Promise链
  })
  .then(value3 => {
    // 处理promise3的成功值
    console.log(value3);
  })
  .catch(error => {
    // 处理任何Promise链中的错误
    console.error(error);
  });