promise-map-series

promise-map-series

Call an iterator function for each element of an array in series, ensuring that no iterator is called before the promise returned by the previous iterator is fulfilled, in effect preventing parallel execution. Like async.mapSeries, but for promises.

Installation

npm install --save promise-map-series

Usage

var mapSeries = require('promise-map-series')

mapSeries(array, iterator[, thisArg]).then(function (newArray) {
  ...
})

• array: An array of value or promises. All promises are resolved before running the iterator. If any are rejected, mapSeries returns a rejected promise immediately and does not call iterator.

• iterator: Function that returns a promise or a value for the new array. The iterator will be called once for each element. If iterator returns a promise, then iterator will only be called for the next element once the promise is fulfilled. If the promise is rejected or iterator throws an error, iteration will stop immediately and mapSeries returns a rejected promise. The iterator function receives three arguments:

  • item: The current item in the array.

  • index: The current index in the array.

  • nonPromiseArray: A copy of the original array with all promises resolved.

• thisArg (optional): Value to use as this when executing iterator.

Changelog

0.1.0

• Initial release