node-resque/src/utils/eventLoopDelay.ts

an opinionated implementation of resque in node

// inspired by https://github.com/tj/node-blocked

export function EventLoopDelay(
  limit: number,
  interval: number,
  fn: (blocked: boolean, delay: number) => any,
) {
  let start = process.hrtime();

  const timeout = setInterval(() => {
    const delta = process.hrtime(start);
    const nanosec = delta[0] * 1e9 + delta[1];
    const ms = nanosec / 1e6;
    const n = ms - interval;
    if (n > limit) {
      fn(true, Math.round(n));
    } else {
      fn(false, Math.round(n));
    }
    start = process.hrtime();
  }, interval);

  if (timeout.unref) {
    timeout.unref();
  }
}