Simple promise throttler function

promiseThrottle.js

const promiseThrottle = (maxParallelCalls = 10) => {
  const queued = [];
  let parallelCalls = 0;
  const abortController = new AbortController();

  const execute = () => {
    if (!queued.length || parallelCalls >= maxParallelCalls) return;

    const { promiseFn, resolve, reject } = queued.shift();
    parallelCalls++;

    if (abortController.signal.aborted) {
      reject(new DOMException('', 'AbortError'));
      queued.splice(0, queued.length);
    } else {
      promiseFn()
        .then(resolve)
        .catch(reject)
        .then(() => {
          parallelCalls--;
          execute();
        })
    }
  };

  const add = (promiseFn) => {
    return new Promise((resolve, reject) => {
      queued.push({
        resolve,
        reject,
        promiseFn
      });

      execute();
    })
  };

  return { add, abort: () => abortController.abort() };
};

export default promiseThrottle;

promiseThrottleExample.js

import promiseThrottle from 'promiseThrottle';

const requestDeferreds = urls.map((url) => (
  throttler.add(() =>
    fetch(url)
  )
));

Promise.all(requestDeferreds)
  .then((data) => {
    conosle.log(data)
  })