Creating array-like objects in JavaScript

Question

In JavaScript, there are objects that pretend to be arrays (or are \"array-like\"). Such objects are arguments, NodeLists (returned from get

Answer 1

Look at this :

var ArrayLike = (function () {

 var result;

 function ArrayLike(n) {

     for (var idx = 0; idx < n; idx++) {
         this[idx] = idx + 1;
     }

     // this.length = Array.prototype.length; THIS WILL NOT WORK !

 }


 // ArrayLike.prototype.splice = Array.prototype.splice; THIS WILL NOT WORK !


 // THIS WILL WORK !
 Object.defineProperty(ArrayLike.prototype, 'length', {

     get: function() {

         var count = 0, idx = 0;

         while(this[idx]) {
             count++;
             idx++;
         }
         return count;

     }

 });


 ArrayLike.prototype.splice = Array.prototype.splice;


 ArrayLike.prototype.multiple = function () {

     for (var idx = 0 ; idx < this.length ; idx++) {

         if (result) {
             result = result * this[idx];
         } else {
             result = this[idx];
         }
     }

     return result;
 };

 return ArrayLike
 })();

var al = new ArrayLike(5);

al.__proto__ = ArrayLike.prototype;

console.log(al.length, al.multiple(), al); 

This will display in Chrome : 5 120 [1, 2, 3, 4, 5]