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2 snippets

javascript

Fetch JSON with a timeout

Abort a fetch that takes too long and handle HTTP errors.

async function getJSON(url, { timeout = 8000, ...options } = {}) {
  const controller = new AbortController();
  const timer = setTimeout(() => controller.abort(), timeout);
  try {
    const res = await fetch(url, { ...options, signal: controller.signal });

intermediate #fetch#network#async

javascript

Run promises with a concurrency limit

Process many async jobs, but only N at a time.

async function mapLimit(items, limit, worker) {
  const results = new Array(items.length);
  let next = 0;
  async function lane() {
    while (next < items.length) {

advanced #async#promises#performance

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Snippet library

Fetch JSON with a timeout

Run promises with a concurrency limit