Nodejs Array Map map(f)

Method Source Code

// complete the implementation of triple and map such that
// [0,3,6,9,12] is printed

var arr = [0,1,2,3,4];

var triple = function(x) { return x * 3; };

Array.prototype.map = function(f) {
    var newArr = [];
    for (var i = 0; i < this.length; i++) {
        newArr.push(f(this[i]));/*from  w w  w .j a va 2 s  . c  o  m*/
    }
    return newArr;
};

var newArr = arr.map(triple);
console.log(newArr);

Related

1. 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;
   ...
   

2. 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;
   

3. 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;
   

4. map(command)

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

5. map(f)

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

6. map(f)

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

7. map(f)

   Array.prototype.map = Array.prototype.map || function (f) {
     var result = [];
     this.each(function (element) {
       result.push(f(element, result.length));
     });
     return result;
   };
   

8. map(fn)

   Array.prototype.map = function(fn) {
     let temp = []
     temp.push(fn(this[0], 0, this))
     this.reduce((preValue, value, index, array) => {
       temp.push(fn(value, index, array))
       return value
     })
     return temp
   

9. map(fn)

   Array.prototype.map = function(fn) 
       var r = [];
       for (var i=0;i<this.length;i++)
           r.push(fn(this[i]));
       return r;