浏览器对同域名的并发数限制

async function fetchWithTimeout(url, options, timeout = 5000) {
  const controller = new AbortController();
  const signal = controller.signal;

  const timeoutId = setTimeout(() => controller.abort(), timeout);

  try {
    const response = await fetch(url, { ...options, signal });
    clearTimeout(timeoutId);
    return response;
  } catch (error) {
    if (error.name === 'AbortError') {
      console.error('Request timed out');
    } else {
      console.error('Request failed', error);
    }
    throw error;
  }
}

async function fetchMultipleUrls(urls) {
  const promises = urls.map(url => fetchWithTimeout(url));
  try {
    const responses = await Promise.all(promises);
    return responses;
  } catch (error) {
    console.error('Failed to fetch all URLs', error);
    throw error;
  }
}

const urls = [
  'https://example.com/api/data1',
  'https://example.com/api/data2',
  'https://example.com/api/data3'
];

fetchMultipleUrls(urls)
  .then(responses => {
    console.log('All requests succeeded', responses);
  })
  .catch(error => {
    console.error('Some requests failed', error);
  });