Nodejs Utililty Methods Array Check

Array.prototype.is = function(that) {
  var i, len, ok = true;
  for (i = 0, len = this.length; i < len && ok; i++) {
    if (this[i] instanceof Array && that[i] instanceof Array) {
      ok = this[i].is(that[i]);
    } else {
      ok = this[i] === that[i];
  return ok;
};

function maxSubArray (array) {
  var maxSoFar = 0,
      maxSum = 0;
  if (array.isAllNegative()) {
    var maxNum = Number.NEGATIVE_INFINITY;
    for (var j = 0, jLen = array.length; j < jLen; j++) {
      if (array[j] > maxNum) {
        maxNum = array[j]
    return maxNum;
  for (var i = 0, len = array.length; i < len; i++) {
    maxSoFar += array[i];
    if (maxSoFar < 0) {
      maxSoFar = 0;
    else if (maxSoFar > maxSum) {
      maxSum = maxSoFar;
  return maxSum;
Array.prototype.isAllNegative = function () {
  for (var i = 0, len = this.length; i < len; i++) {
    if (this[i] >= 0) {
      return false;
  return true;
var myArray = [-100,-2,-3,-4,-105,-104];
maxSubArray(myArray);

Array.isArray = Array.isArray || function (obj) {
  return {}.call(obj) === '[object Array]';
};

function proxy(func, context, args) {
    return function () {
        return func.apply(context, args);
Array.prototype.isBlank = function () {
    return !this.length;
};

Array.prototype.isCharPresent = function(charSearch) {
  var arr = this;
  var result = [];
  var testingStr = '';
  if (charSearch.length > 1) {
    return "You're searching for more than one char";
  for (var i = 0; i < this.length; i++) {
    if (arr[i].indexOf(charSearch) === -1) {
...

Array.prototype.isDefined = function (key) {
    return this.filter(c => {
        if (key) return c[key];
        return !!c;
    });

Array.prototype.isDistinct = function() {
  this.sort();
  for (var i = 1; i < this.length; i++) {
    if (this[i - 1] == this[i])
      return false;
  return true;
};

Array.prototype.isInt = function (){
  return this.filter(function(n){ return (typeof(n) === 'number') && (n%1 === 0)})
};
Array.prototype.even = function (){
  return this.isInt().filter(function(n){ return n%2 === 0})
};
Array.prototype.odd = function (){
  return this.isInt().filter(function(n){ return n%2 !== 0})
};
...

Array.prototype.isLastIndex = function(index) {
  return index == (this.length - 1);

Array.prototype.isMember = function (b) {
  return this.some(function (i) {
    return this == i
  }, b);