Nodejs Array ForEach forEach(callback)

Method Source Code

Array.prototype.forEach = Array.prototype.forEach || function (callback) {
    var self = this;
    for (var i = 0; i < self.length; i++) {
        var item = self[i];
        callback(item, i, self);//from www . j a v a  2  s  . c om
    }
}

Related

1. forEach()

   Array.prototype.forEach = Array.prototype.forEach || _forEach
   Array.prototype.every = Array.prototype.every || _every
   Array.prototype.indexOf = Array.prototype.indexOf || function(member) {
     for(var idx = 0; idx < this.length; ++idx) {
       if(this[idx] === member) {
         return idx
     return -1
   ...
   

2. forEach(a)

   "use strict"
   Array.prototype.forEach = function(a) {
     for (let i = 0; i < this.length; i++) a(this[i], i, this)
   

3. forEach(action, index)

   Array.prototype.forEach = Array.prototype.forEach || function(action, index) {
       for (var i=0,l=this.length; i<l; i++) {
           action(this[i], index);
   };
   

4. forEach(callback)

   Array.prototype.forEach = function(callback){
       let arr = this;
       for (var i = 0; i < arr.length; i++) {
           callback(arr[i], i, arr);
   

5. forEach(callback)

   Array.prototype.forEach = function(callback){
     var a = 0,
       len = this.length;
     while(a < len){
       callback(this[a], a++, this);
   };
   

6. forEach(callback, context)

   Array.prototype.forEach = Array.prototype.forEach || function (callback, context) {
     context = context || window;
     var l = this.length;
     for (var i = 0; i < l; i++)
       callback.call(context, this[i], i, this);
   };
   

7. forEach(callback, context)

   Array.prototype.forEach = function (callback, context) {
       for (var index in this) {
           var item = this[index];
           if (!callback(index, item, context)) {
               break;
   };
   

8. forEach(callback, thisArg)

   Array.prototype.forEach = function (callback, thisArg) {
     if (typeof callback !== 'function') {
       throw new TypeError(callback + ' is not a function.');
     var len = this.length;  
     for (var i = 0; i < len; i++) {
       callback.call(thisArg, this[i], i, this);
   };
   ...
   

9. forEach(cb)

   Array.prototype.forEach = function(cb){
     for(var k in this) cb(this[k]);
   };