Nodejs Array Map mapper(callback)

Method Source Code

Array.prototype.mapper = function(callback){
    var arr = [];
    //from  w  w  w .jav  a  2  s  .  co  m
    for (var i = 0; i < this.length; i++)
        callback(this[i]);
        
    return arr;
};




var arr = [1, 2, 3];
Array.prototype.mapper = function(callback){
    for (var i = 0; i < this.length; i++)
        this[i] = callback(this[i]);
};

arr.mapper();
console.log(arr) // -> [2,4,6]

Related

1. map2(projection)

   const stocks= [
     {symbol: 'XFX', price: 240.22, volume: 23432},
     {symbol: 'TNZ', price: 332.19, volume: 234},
     {symbol: 'JXJ', price: 120.22, volume: 5323},
   ]
   Array.prototype.map2= function(projection) {
     let results= []
     this.forEach(item => results.push(projection(item)))
     return results
   ...
   

2. mapByTwo(fun /*, thisp*/)

   Array.prototype.mapByTwo = function(fun ) {
     if (typeof fun != "function")
       throw new TypeError();
     var len = this.length >>> 0;
     var thisp = arguments[1];
     var k = 0;
     var A = new Array(Math.ceil(len/2));
     if (len/2 < A.length) {
       this.push(null);
   ...
   

3. mapMe(func)

   Array.prototype.mapMe = function (func) {
     var arr = this, result = [];
     for (var i = 0; i < arr.length; i++) {
       result.push(func(arr[i]));
     return result;
   };
   

4. mapValues(value)

   Array.prototype.mapValues = function(value) { 
       return this.map(function(e) { 
           return e[value] 
       })
   

5. mapp(callback)

   Array.prototype.mapp = function(callback) {
     var newArray = [];
     for(var i = 0; i < this.length; i++){
       newArray.push(callback(this[i]));
     return newArray;
   var x = [1,2,3];
   x.mapp(function(ele) {
   ...
   

6. mapx(f,t)

   Array.prototype.mapx=function(f,t){
     var b=this.length,a=new Array(b);
     for(var i=0;i<b;i++){
       a[i]=f.call(t,this[i],i,this);
     return a;