Nodejs Array Map map(callback)

Method Source Code

Array.prototype.map = function(callback) {
   var result = [];
   this.forEach(function(item) {
      result.push(callback(item));/*  w ww  .ja  v  a  2  s. co m*/
   });

   return result;
};

//concatAll() only works on singly nested arrays
//for example: [["a", ["test"]]] returns ["a", >Array[1]]
Array.prototype.concatAll = function(array) {
   var results = [];
   this.forEach(function(subArray) {
    if (Array.isArray(subArray)) {
      subArray.forEach(function(item) {
         results.push(item);
      });
    } else {
       results.push(item);
    }
   });

   return results;
};

var test = [["Build"], ["a"], ["bird's"], ["nest"], ["to"], ["make", "a"], ["test"]];
test.concatMap(function(item) {
   return item;
});

Related

1. map(callback)

   Array.prototype.map = function(callback) {
     let res = [];
     this.forEach(el => res.push(callback(el)));
     return res;
   };
   let a = [1,2,3];
   let b = a.map(el => el * el);
   console.log(a);
   console.log(b);
   ...
   

2. map(callback)

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

3. 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]
   ...
   

4. 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;
   

5. map(callback)

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

6. map(callback)

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

7. map(callback, thisArg)

   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');
     for(var i = 0, len = this.length; i < len; i++){
       newArr[i] = callback.call(thisArg, this[i], i , this);
     };
     return newArr;
   ...
   

8. 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;
   ...
   

9. 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;