@architect/deploy/src/utils/tiny-each-async.js

Deploys @architect projects

'use strict'

module.exports = function eachAsync (arr, parallelLimit, iteratorFn, cb) {
  var pending = 0
  var index = 0
  var lastIndex = arr.length - 1
  var called = false
  var limit
  var callback
  var iterate

  if (typeof parallelLimit === 'number') {
    limit = parallelLimit
    iterate = iteratorFn
    callback = cb || function noop () {}
  }
  else {
    iterate = parallelLimit
    callback = iteratorFn || function noop () {}
    limit = arr.length
  }

  if (!arr.length) { return callback() }

  var iteratorLength = iterate.length

  function shouldCallNextIterator () {
    return (!called && (pending < limit) && (index < lastIndex))
  }

  function iteratorCallback (err) {
    if (called) { return }

    pending--

    if (err || (index === lastIndex && !pending)) {
      called = true

      callback(err)
    }
    else if (shouldCallNextIterator()) {
      processIterator(++index)
    }
  }

  function processIterator () {
    pending++

    var args = (iteratorLength === 2) ? [ arr[index], iteratorCallback ]
      : [ arr[index], index, iteratorCallback ]

    iterate.apply(null, args)

    if (shouldCallNextIterator()) {
      processIterator(++index)
    }
  }

  processIterator()
}