Process a list with configurable in the middle as to not block the main thread

async-map.ts

type AsyncMapParams = {
  timeout: number;
  steps: number;
  coolDown?: number;
}

const asyncMap = async <I, O>(inList: I[], fn: (input: I) => O, inParams: AsyncMapParams): Promise<O[]> => {
  const params = Object.assign({}, {
    timeout: 16,
    coolDown: 16,
    steps: 10_000,
  }, inParams);

  const outList = new Array<O>(inList.length);

  let startTime = performance.now();

  for (let i = 0; i < inList.length; i++) {
    if (i % params.steps === 0) {
      if (performance.now() - startTime > params.timeout) {
        await new Promise(res => setTimeout(res, params.coolDown));
        startTime = performance.now()
      }
    }

    try {
      outList[i] = fn(inList[i]);
    } catch (error) {
      outList[i] = error;
    }
  }

  return outList;
};