promise-backoff-strategy.js

const pause = (duration) => new Promise(res => setTimeout(res, duration));

const retry = (retries, fn) =>
    fn().catch(err => retries > 1 ? retry(retries - 1, fn) : Promise.reject(err));

const backoff = (retries, fn, delay = 500) =>
    fn().catch(err => retries > 1
        ? pause(delay).then(() => backoff(retries - 1, fn, delay * 2))
        : Promise.reject(err));