retry with async/await

retry.js

import delay from 'delay'

const createAttempter = (worker) => async () => {
  let retval, error, time
  const startTime = Number(new Date())
  try {
    retval = await worker()
  } catch (err) {
    error = err
  }
  time = new Date() - startTime
  return {retval, error, time}
}

const retry = async (work, {interval, attempts}) => {
  const attempt = createAttempter(work)
  let result = await attempt()
  let attemptCount = 1
  while (result.error != null && attemptCount < attempts) {
    if (result.time < interval) {
      await delay(interval - result.time)
    }
    result = await attempt()
    ++attemptCount
  }
  if (result.error != null) {
    throw result.error
  }
  return result.retval
}