apiplex

A zero-dependency async multiplexer for API calls and other async tasks. Run many tasks with a concurrency cap, aggregate results by name, tolerate individual failures, and rate-limit callers.

Pricing

Free. MIT-licensed, open source. No fees, no tiers.

Install

npm install apiplex

Usage

const { multiplex, runAll, rateLimited } = require("apiplex");

// Fan out several API calls, run at most 3 at a time, keep going on failures
const { results, errors } = await multiplex(
  {
    users: () => fetch("/users").then(r => r.json()),
    posts: () => fetch("/posts").then(r => r.json()),
    stats: () => fetch("/stats").then(r => r.json()),
  },
  { concurrency: 3, onError: (err, name) => console.error(name, err.message) }
);
console.log(results.users, results.posts); // per-key results
if (errors.stats) { /* that one failed but others completed */ }

// Or: run all, fail fast on the first rejection
const all = await runAll({ a: () => ..., b: () => ... }, 2);

// Rate-guard a function (max 10 calls/second)
const guarded = rateLimited(expensiveFn, { rate: 10, windowMs: 1000 });
guarded(); // ... excess calls within the window return undefined

API

• multiplex(tasks, { concurrency, breakOnError, onError }) → { results, errors }
• runAll(tasks, concurrency?) → results (rejects on first failure)
• rateLimited(fn, { rate, windowMs }) → guarded fn

License

MIT © shinnjr