Nodejs Array Find find(callback)

Method Source Code

'use strict';/*from w  ww . j  a va  2  s  . com*/

Array.prototype.find = Array.prototype.find || function(callback) {
  if (this === null) {
    throw new TypeError('Array.prototype.find called on null or undefined');
  } else if (typeof callback !== 'function') {
    throw new TypeError('callback must be a function');
  }
  var list = Object(this);
  // Makes sures is always has an positive integer as length.
  var length = list.length >>> 0;
  var thisArg = arguments[1];
  for (var i = 0; i < length; i++) {
    var element = list[i];
    if ( callback.call(thisArg, element, i, list) ) {
      return element;
    }
  }
}

Related

1. find( func)

   Array.prototype.find = function( func) {
     if( $.isFunction(func) ) {
       for( var i=0; i<this.length; i++ ) {
         var item = this[i];
         if( func(item) == true ) {
           return item;
       return null;
   ...
   

2. find()

   Array.prototype.find = function() {
     if(arguments.length === 0) {
       return CollectionInspect(this);
   };
   

3. find()

   Array.prototype.find = function()
     var result;
       this.each(function(value, index)
       if(iterator.call(context, value, index, this))
         result = value;
         return false;
   ...
   

4. find(callback)

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

5. find(cond)

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

6. find(criteria)

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

7. find(criteria)

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

8. find(element)

   Array.prototype.find = function (element) {
     if (typeof element === 'function') {
       return element(this);
     var len = this.length;
     for (var i = 0; i < len; i++) {
       if(this[i] === element) {
         return element;
     return -1;
   var doPow = function (array) {
     var len = array.length;
     for(var i = 0; i < len; i++) {
       array[i] *= array[i]; 
     return array;
   var b = [1, 2, 3, 4, 5, 6];
   console.log(b.find(doPow));