module.exports = function array_filter(arr, func) {
  //  discuss at: https://locutus.io/php/array_filter/
  // original by: Brett Zamir (https://brett-zamir.me)
  //    input by: max4ever
  // improved by: Brett Zamir (https://brett-zamir.me)
  //      note 1: Takes a function as an argument, not a function's name
  //   example 1: var odd = function (num) {return (num & 1);}
  //   example 1: array_filter({"a": 1, "b": 2, "c": 3, "d": 4, "e": 5}, odd)
  //   returns 1: {"a": 1, "c": 3, "e": 5}
  //   example 2: var even = function (num) {return (!(num & 1));}
  //   example 2: array_filter([6, 7, 8, 9, 10, 11, 12], even)
  //   returns 2: [ 6, , 8, , 10, , 12 ]
  //   example 3: array_filter({"a": 1, "b": false, "c": -1, "d": 0, "e": null, "f":'', "g":undefined})
  //   returns 3: {"a":1, "c":-1}

  let retObj = {}
  let k

  func =
    func ||
    function (v) {
      return v
    }

  // @todo: Issue #73
  if (Object.prototype.toString.call(arr) === '[object Array]') {
    retObj = []
  }

  for (k in arr) {
    if (func(arr[k])) {
      retObj[k] = arr[k]
    }
  }

  return retObj
}