[glasser]

The surprise isn't that the memory associated with `logIt` is leaked.

The surprise is that `logIt` holds on to the giant `str` object in its environment, despite the fact that there is literally no way for the `str` variable to ever be used again.

V8 is smart enough to not make `logIt` hold on to `str` if there are no closures at all which refer to `str`. It's the introduction of the unrelated `doSomethingWithStr` closure that forces `str` into the lexical environment.

[glasser]

BTW, the original bug in the Meteor codebase wasn't a setInterval.

It was that code to replace a certain type of object (a Spark renderer) with a new instance of that object accidentally ended up with a reference to the preceding renderer in a closure assigned somewhere on it, even though that particular closure didn't actually use that reference.

So instead of replacing renderer #N with renderer #(N+1) and GCing #N, we ended up with a stream of renderers which never could be GCed... even though the reference keeping the old ones alive was literally impossible to ever use.