中文
devexamples

P-Limit Concurrency Control for Task Queues

Cap parallel task execution with p-limit so large batches of promises run at a fixed concurrency instead of exhausting memory or API quotas.

JavascriptResilience

Code

snippet
import pLimit from 'p-limit';

const limit = pLimit(4);

async function syncAll(ids) {
  const tasks = ids.map((id) =>
    limit(() => fetch(`https://api.example.com/items/${id}`).then((r) => r.json())),
  );
  const results = await Promise.all(tasks);
  return results;
}

const started = [];
const tracker = pLimit(2);
const jobs = [1, 2, 3, 4].map((n) =>
  tracker(async () => {
    started.push(n);
    console.log('running', n, 'active:', started.length);
    await new Promise((r) => setTimeout(r, 100));
    started.pop();
  }),
);
await Promise.all(jobs);

Related Examples