exponential-backoff

exponential.js

function createScheduler({
  callback,
  time,
  callbackTimeout,
  backoffMultiplier = 1.5,
  backoffMaxTime = 20000
}) {
  let run;
  let timeoutId;
  let ticker;

  function pause(time) {
    return new Promise(resolve => {
      timeoutId = setTimeout(resolve, time);
    });
  }

  async function* cycle(time) {
    let currentWaitTime = time;
    run = true;

    while (run) {
      const error = yield pause(currentWaitTime);
      if (error) {
        currentWaitTime = Math.min(
          currentWaitTime * backoffMultiplier,
          backoffMaxTime
        );
      } else {
        currentWaitTime = Math.max(currentWaitTime / backoffMultiplier, time);
      }
    }
  }

  async function runPeriodically() {
    if (!ticker || !run) {
      ticker = cycle(time);
    }

    let item = await ticker.next();

    while (!item.done) {
      try {
        if (callbackTimeout) {
          await Promise.race([
            callback(),
            pause(callbackTimeout).then(() => {
              throw new Error("Callback timeout");
            })
          ]);
        } else {
          await callback();
        }
        item = await ticker.next();
      } catch (error) {
        item = await ticker.next(error);
      }
    }
  }

  function stop() {
    clearTimeout(timeoutId);
    run = false;
  }

  return {
    runPeriodically,
    stop
  };
}