Question

I want to retrieve all objects (not DOM elements) of a given type created with the “new” keyword.

Is it possible ?

function foo(name)
{
  this.name = name;
}

var obj = new foo();

How can I retrieve a reference to all the foo objects ?

Answer 1

If they were all assigned in the global scope, and you don’t need to check across iframe/window boundaries, and you do not need to do this in IE (eg you’re just trying to debug something), you should be able to iterate over the global scope:

var fooObjects = [];
for(var key in window) {
  var value = window[key];
  if (value instanceof foo) {
    // foo instance found in the global scope, named by key
    fooObjects.push(value)
  }
}

Buuuuut you probably have some foos instantiated inside functions somewhere, in which case they’re not available.

You can perhaps try modifying the constructor prior to instantiations:

var fooObjects = [];
var oldFoo = window.foo;
window.foo = function() {
  fooObjects.push(this);
  return oldFoo.apply(this, arguments);
}

foo.prototype = oldFoo.prototype;