Firstly, sorry for my lack of terminology.

If I have a constructor

function myObject(name, value){
    this.name = name;
    this.value = value;
}

and I make a few objects from it

var One = new myObject("One", 1);
var Two = new myObject("Two", 2);

Can I loop through each new Object made from the myObject class, without putting each new Object into an Array?

would it be possible to add an Instantly Invoking Function to the constructor that adds the Object into an array?

e.g.

function myObject(name, value){
    this.name = name;
    this.value = value;

    this.addToArray = function(){
        theArray.push(this);        // this is the IIFE
    }(); 
}

that way any new objects created instantly run this function and get added to the array.

Is this possible? ( current syntax does not work, obviously )

EDIT Coming back to this one year later I can tell you that it IS possible. You just call the function inside the constructor like so:

function myObject(name, value){
    this.name = name;
    this.value = value;

    this.addToArray = function(){
        theArray.push(this);
    };

    this.addToArray();

}

Here is an example of this in JSFIDDLE, pushing each object into an array on instantiation and then calling each object's .speak() method directly from the array.

/

Firstly, sorry for my lack of terminology.

If I have a constructor

function myObject(name, value){
    this.name = name;
    this.value = value;
}

and I make a few objects from it

var One = new myObject("One", 1);
var Two = new myObject("Two", 2);

Can I loop through each new Object made from the myObject class, without putting each new Object into an Array?

would it be possible to add an Instantly Invoking Function to the constructor that adds the Object into an array?

e.g.

function myObject(name, value){
    this.name = name;
    this.value = value;

    this.addToArray = function(){
        theArray.push(this);        // this is the IIFE
    }(); 
}

that way any new objects created instantly run this function and get added to the array.

Is this possible? ( current syntax does not work, obviously )

EDIT Coming back to this one year later I can tell you that it IS possible. You just call the function inside the constructor like so:

function myObject(name, value){
    this.name = name;
    this.value = value;

    this.addToArray = function(){
        theArray.push(this);
    };

    this.addToArray();

}

Here is an example of this in JSFIDDLE, pushing each object into an array on instantiation and then calling each object's .speak() method directly from the array.

https://jsfiddle/Panomosh/8bpmrso1/

• javascript
• javascript-objects

• Is Object.keys(One); what you need? – NMunro Commented Jul 2, 2015 at 9:13
• You can't, nothing keep a reference to your objects. – Hacketo Commented Jul 2, 2015 at 9:15
• Basically I want to be able to See each Object that I have created from the myObject Constructor. – Josh Stevenson Commented Jul 2, 2015 at 9:15
• possible duplicate of stackoverflow./questions/2602800/… – andy mccullough Commented Jul 2, 2015 at 9:22

3 Answers 3

Without using an array, you can't, it is not the way it is meant to be used.

What you can do though, is watch over each instances created in a static member of myObject class

function myObject(name, value){
    this.name = name;
    this.value = value;

    this.watch();
}

myObject.prototype.watch = function () {
    if (myObject.instances.indexOf(this) === -1) {
        myObject.instances.push(this);
    }
};

myObject.prototype.unwatch = function () {
    myObject.instances.splice(myObject.instances.indexOf(this), 1);
};

myObject.instances = [];

No, you cannot. You cannot do this with almost all programming languages.

You can, in the constructor, store a reference of every object you created into an array/map so that you can iterate over them any time. This, however, prevents all objects of this class from being garbage collected, so use it with care.

The WeakMap in JavaScript keeps only a week reference to the keys, but it, in turn, does not allow you to loop over all keys. So it is not an option either.

var MyClass = (function() {
  var _instances = [];

  function MyClass(name, value) {
    _instances.push(this);

    this.name = name;
    this.value = value;
  }

  MyClass.each = function(cb) {
    for (var i in _instances) {
      if (_instances.hasOwnProperty(i)) {
        cb(_instances[i]);
      }
    }
  }

  return MyClass;

})();

new MyClass('John', 10);
new MyClass('James', 20);

MyClass.each(function(item) {
  console.log(item);
});