Nodejs Utililty Methods Array Find

Array.prototype.find=function(element){
    var i;
    for(i=0;i<this.length;i+=1){
        if(this[i]===element){
            return i;
    return false;
Array.prototype.remove=function(element){
    var i;
    for(i=0;i<this.length;i+=1){
        if(this[i]===element){
            this.splice(i,1)
            return true;
    return false;
var arr=['a','b','c','d','e','f','g','h'];
arr.remove('e');
arr.remove('f');
var i;
for(i=0;i<arr.length;i+=1){
    console.log(arr[i]);

Array.prototype.find = function(f) {
  for (var i = 0; i < this.length; i++) {
    if (f(this[i]))
      return this[i];
};

Array.prototype.find = function(filter) {
  if(typeof filter != 'function') {
    throw new Error('First argument must be a function');
  for(var i=0; i<this.length; i++) {
    var element = this[i];
    if(filter(element, i)) {
      return element;
};

Array.prototype.find = function(fn) {
    for (var i = 0; i < this.length; i++) {
        if (fn(this[i])) {
            return this[i];

Array.prototype.find = function(fn, v) {
    var isFN = typeof(fn) === 'function';
    var isV = v !== undefined;
    for (var i = 0, len = this.length; i < len; i++) {
        if (isFN) {
            if (fn(this[i], i)) {
                return this[i];
            continue;
...

Array.prototype.find = function(id) {
  return this.filter(function(a) {
    if ( a.id == id ) {
      return a;
  }).first();

const array = [1, 42, 7, 9, 13, 10, 20, 35, 45, -7, -3, 0, 4, -1, 15];
Array.prototype.find = function(isOk) {
  const len = this.length;
  for(let i = 0; i < len; i += 1) {
    if(isOk(this[i], i, this)) {
      return this[i];
Array.prototype.findIndex = function(isOk) {
  const len = this.length;
  for(let i = 0; i < len; i += 1) {
    if(isOk(this[i], i, this)) {
      return i;
  return -1;
console.log(array.find(x => x % 2 === 0));
console.log(array.find(x => x % 2 === 1));
console.log(array.find(x => x > 10 && x < 20));
console.log(array.find(x => x === 45));
console.log(array.find(x => x === 46));
console.log(array.findIndex(x => x % 2 === 0));
console.log(array.findIndex(x => x % 2 === 1));
console.log(array.findIndex(x => x > 10 && x < 20));
console.log(array.findIndex(x => x === 45));
console.log(array.findIndex(x => x === 46));

Array.prototype.find = function(predicate) {
    if (this == null) {
        throw new TypeError('Array.prototype.find called on null or undefined');
    if (typeof predicate !== 'function') {
        throw new TypeError('predicate must be a function');
    var list = Object(this);
    var length = list.length >>> 0;
...

Array.prototype.find = function(predicate){
    var list = Object(this);
    var length = list.length >>> 0;
    var thisArg = arguments[1];
    var value;
    for (var i = 0; i < length; i++) {
        value = list[i];
        if (predicate.call(thisArg, value, i, list)) {
            return value;
...

Array.prototype.find = function (predicateFn) {
  for (var i = 0; i < this.length; i++) {
    if ( predicateFn(this[i]) ) return this[i]
  return null