Promise重试机制实战解析

function retry(fn, times = 3) {
  return fn().catch(err => {
    if (times  setTimeout(() => resolve(), 1000))
      .then(() => retry(fn, times - 1));
  });
}
// 使用
retry(() => fetch('/api/data'))
.then(res => res.json())
.catch(err => console.error('最终失败:', err));

function retryAsync(fn, options = {}) {
  const {
    maxRetries = 3,
    baseDelay = 500,
    shouldRetry = (err) => err instanceof TypeError || /network|fetch/i.test(err.message),
    signal
  } = options;
const attempt = (n) => {
return fn().catch(async (err) => {
if (n >= maxRetries || !shouldRetry(err)) throw err;
if (signal?.aborted) throw new Error('Retry aborted');
  const delay = baseDelay * Math.pow(2, n);
  await new Promise(r => setTimeout(r, delay));
  return attempt(n + 1);
});
};
return attempt(0);
}

const controller = new AbortController();
setTimeout(() => controller.abort(), 10000); // 总超时 10 秒
retryAsync(
() => fetch('/api/orders', { signal: controller.signal }),
{
maxRetries: 4,
baseDelay: 300,
shouldRetry: (err) => 
err.name === 'TypeError' || // 网络断开
(err.response?.status >= 500) // 服务端错误才重试
}
)
.then(res => res.json())
.catch(err => {
if (err.name === 'AbortError') console.log('请求被取消');
else console.error('重试耗尽', err);
});

async function loadData() {
  try {
    const res = await retryAsync(
      () => fetch('/api/user'),
      { maxRetries: 2 }
    );
    return await res.json();
  } catch (err) {
    throw new Error(`加载用户失败：${err.message}`);
  }
}