retry.js

import {Retry} from './intern/Until'

/**
* Run `task` max. `times` times. Stops at first iteration where no error is returned.
*
* Calls next `.then()` if `times` is reached or `task` returned no error,
* otherwise next `.catch()`.
*
* @name retry
* @memberOf module:serial
* @static
* @method
* @param {Number|Object} times - retry max. `times` times - default=2
* @param {Number} [times.times=2] - max. number of retries
* @param {Number} [times.lag=0] - time-lag in ms between retries
* @param {Function} task - iterator function of type `(index: Number) => Promise`
* @return {Promise}
*
* @example
* retry({times: 3, lag: 100}, // max. 3 retries with 100ms time-lag between retries
*   (index) => new Promise((resolve, reject) => {
*     let err = index < 2 ? new Error() : null
*     if (err) reject(err)
*     else resolve(index)
*   })
* ).then((res) => {
*   //> res = 2
* })
*/
export default function retry (times, task) {
  let opts = {}
  if (typeof times === 'object') {
    opts = times
    times = times.times
  }
  return new Promise((resolve, reject) => {
    new Retry(times || 2, task, opts, resolve, reject)
  })
}