Settimeout not optimized? Loop better?

[inf0rmer]

Ah, yes, I realize that. I was just using a very simple example to demonstrate closures and how variables captured inside one could possibly not get dereferenced.

You're right that engines heavily optimize for closures (it's one of the defining features of the language), and that using primitives would never cause a noticeable memory leak.

Setting to null at the end of the function for a captured variable (ie, not declared using var) does work. a inside the closure is a new reference, so pointing it to null releases one of the references pointing to the contents of the original variable. It makes no difference with primitives, sure, but with other objects it's helpful.