Question

If I were to define two objects myDataStore and myDrawer something like this:

var myDataStore = function(myObjectRef) {
    this.myInternalObject = myObjectRef;
};

var myDrawer = function(myObjRef) {
    this.myInternalObject = myObjectRef;
};

And if I were to create an object like so:

[[EDIT – Adjusted Object Creation to Ensure ‘this’ is being mapped to myObject, not the global window object]]

(function(){
  var myObject = window.myObject = function(){
      this.dataStore = new myDataStore(this);
      this.drawer = new myDrawer(this);
  }
 })();

Then myObject.dataStore.myInternalObject, and myObject.drawer.myInternalObject, would simply be pointers back to the original ‘myObject’ – not taking up any additional memory in the browser. Yes?

I am interested in implementing techniques like this – as it makes it easy for objects to communicate with each other.

Answer 1

Yes, your assumption is correct. myInternalObject will be a reference and not a new object. You can test it like this:

var MyDataStore = function(myObjectRef) {
    this.myInternalObject = myObjectRef;
};

var data = {
    value: "value"
};
var dataStore = new MyDataStore(data);
data.value = "test";
console.log(dataStore.myInternalObject);  // logs { value : "test" } instead of { value: "value" }