Nodejs Utililty Methods Array Flatten

Array.prototype.flatten = function() {
    var result = [];
    function checkForArrays(arr) {
        arr.forEach(function(el) {
            if (Array.isArray(el)) {
                checkForArrays(el);
            }else {
                result.push(el);
        })
    checkForArrays(this);
    return result;
};
var array = [1, 2, 3, 4];
console.log(array.flatten());

function flatten (ary) {
  var ret = []
  for (var i = 0; i < ary.length; i++) {
    if (Array.isArray(ary[i])) {
      ret = ret.concat(flatten(ary[i]))
    } else {
      ret.push(ary[i])
  return ret
Array.prototype.flatten = function () {
  var ret = []
  for (var i = 0; i < this.length; i++) {
    if (Array.isArray(this[i])) {
      ret = ret.concat(this[i].flatten())
    } else {
      ret.push(this[i])
  return ret
function flattenReduce (ary) {
  return ary.reduce(function (a, b) {
    if (Array.isArray(b)) {
      return a.concat(flattenReduce(b))
    return a.concat(b)
  }, [])

Array.prototype.flatten = function (){
    var array = this;
    var newArray = [];
    recursive(array);
    function recursive (arr){
        for (var i = 0; i < arr.length; i++) {
            if (arr[i] instanceof Array) {
                recursive(arr[i]);
            } else {
...

Array.prototype.flatten = function(){
    var array = this;
    var processedArray = [];
    for(var i = 0; i < array.length; i++){
        if(array[i] instanceof Array){
            var subArray = array[i].flatten();
            processedArray.push.apply(processedArray,subArray);
        else {
...

Array.prototype.flatten = function() {
    function getArrayElements(array, result) {
        if(!result) {
            result = [];
        for (var i=0; i<array.length; i++) {
            if(Array.isArray(array[i])) {
                getArrayElements(array[i], result);
            }else {
...

Array.prototype.flatten = function() {
    return this.inject([], function(array, value) {
      if (DiaFluxUtils.isArray(value))
        return array.concat(value.flatten());
      array.push(value);
      return array;
    });

Array.prototype.flatten = function(){
  return this.reduce(function(flat, val, i, hilly){
    Array.isArray(val) ? flat.concat(val.flatten()) : flat.concat(val);
  }, []);

Array.prototype.flatten = function () {
    var result = [];
    function flatten(elements, output) {
        elements.forEach(function (element) {
            if (!(typeof element === 'object' || typeof element === typeof Array)) {
                output.push(element);
            else {
                flatten(element, output);
...

Array.prototype.flatten = function() {
    return Array.prototype.concat.apply([], this);

Array.prototype.flatten = function() {
    var resultArray = [];
    function getValues(array) {
        var i;
        for (i = 0; i < array.length; i += 1) {
            var value = array[i];
            if (Array.isArray(value)) {
                getValues(value);
            } else {
...