js promise 链式调用

// 创建一个Promise
const fetchData = () => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve('Data fetched');
    }, 1000);
  });
};

// 链式调用
fetchData()
  .then(data => {
    console.log(data); // 输出: Data fetched
    return 'Processed data';
  })
  .then(processedData => {
    console.log(processedData); // 输出: Processed data
    throw new Error('Something went wrong');
  })
  .catch(error => {
    console.error(error.message); // 输出: Something went wrong
  });

fetchData()
  .then(data => {
    if (data === 'error') throw new Error('Data error');
    return data;
  })
  .then(processedData => {
    console.log(processedData);
  })
  .catch(error => {
    console.error(error.message);
  });

const fetchAndProcessData = () => {
  return fetchData()
    .then(data => processData(data))
    .then(finalData => console.log(finalData));
};

const processData = data => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(`Processed ${data}`);
    }, 500);
  });
};

fetchAndProcessData().catch(console.error);