Could someone explaine to me why below code does not cause any memory leaks? My understanding is variable originalThing is being used in closure unCalled and theroetically referenced by closure someMethod, hence originalThing should not be garbage collected, but i do not see memory leak at all when i was profiling it in browser.

<script>
var theThing = new Array(1000000000);
var replaceThing = function () {
  var originalThing = theThing;
 
  var unCalled = function () {
    if (originalThing)
      return originalThing
  };
  var obj = {
    longStr: new Array(1000000).join('*'),
    someMethod: function () {}
  };
};
setInterval(replaceThing, 1000);
</script>

But if i changed variable obj to theThing then it would cause memory leak, please see code below:

<script>

var theThing = new Array(1000000000);
var replaceThing = function () {
  var originalThing = theThing;
 
  var unused = function () {
    if (originalThing)
      console.log("Hi")
  };
   theThing = {
    longStr: new Array(1000000).join('*'),
     someMethod: function () {}
  };
 
};
setInterval(replaceThing, 1000);
</script>

So what difference deos it make in terms of memory leak caused by closure?