Nodejs Array Map map(callback, thisArg)

Method Source Code

Array.prototype.map = function(callback, thisArg){
   var newArr = [];
   if(callback && Object.prototype.toString.call(callback) != "[object Function]"){
      throw new TypeError('callback is not a function');
   }/*w w  w. j a  va  2 s  .  c om*/
   for(var i = 0, len = this.length; i < len; i++){
      newArr[i] = callback.call(thisArg, this[i], i , this);
   };
   return newArr;
};
function fn(value, i , obj){
   return value*2;
}
var newarr = [1,2,3,4].map(fn);

Related

1. map(callback)

   Array.prototype.map = function(callback){
       const newArr = []
       for(let i = 0; i < this.length; i += 1){
           let newValue = callback(this[i])
           newArr.push(newValue)
       return newArr
   var someArray = [1,2,3,4]
   ...
   

2. map(callback)

   Array.prototype.map = function(callback) {
     for(var i = 0, l = this.length; i < l; i++) {
       this[i] = callback(i, this[i]);
     return this;
   

3. map(callback)

   Array.prototype.map = function (callback) {
     var mapped = [];
     function mutation(el) {
       mapped.push(callback(el));
     this.each(mutation);
     return mapped;
   };
   

4. map(callback)

   Array.prototype.map = function(callback) {
     var result = [];
     this.forEach(function(item) {
       result.push(callback(item));
     });
     return result;
   };
   Array.prototype.concatAll = function(array) {
     var results = [];
   ...
   

5. map(callback)

   Array.prototype.map = function(callback) {
     var returnArray=[];
     for (var i=0; i<this.length; i++) {
       returnArray.push(callback(this[i]));
     return returnArray;
   };
   

6. map(callback, thisArg)

   Array.prototype.map = Array.prototype.map || (function(callback, thisArg) {
     var T, A, k;
     var O = Object(this);
     var len = O.length >>> 0;
     if (arguments.length > 1) T = thisArg;
     A = new Array(len);
     k = 0;
     while (k < len) {
       var kValue, mappedValue;
   ...
   

7. map(callbackfn, thisArg)

   Array.prototype.map = function (callbackfn, thisArg) {
     var res = [];
     for (var i=0; i<this.length; i++)
       res[i] = Kernel.Reflect.apply(callbackfn, thisArg, [this[i], i, this]);
     return res;
   

8. map(cb)

   Array.prototype.map = function(cb){
       var arr = Object(this);
       var res = []
       for(var i=0;i<arr.length;i++){
           res[i] = cb.call(arr[i], i);
       return res;
   

9. map(command)

   Array.prototype.map = function(command){
     var outArray = [];
     this.each(function(x){
       outArray.push(command(x));
     });
     return outArray;
   };