Promise.all(), Promise.race(), and Promise.any()

const urls = ['api/1', 'api/2', 'api/3'];
const limits = {
  concurrency: 2,
  timeout: 5000
};

async function fetchWithLimits(urls, limits) {
  const results = [];
  for (let i = 0; i < urls.length; i += limits.concurrency) {
    const batch = urls.slice(i, i + limits.concurrency)
      .map(url => timeout(fetch(url), limits.timeout));
    results.push(...await Promise.allSettled(batch));
  }
  return results;
}