

Partial loop unrolling in JavaScript - defun-fun
http://james.padolsey.com/javascript/partial-loop-unrolling/

======
btilly
[http://fatagnus.com/unrolling-your-loop-for-better-
performan...](http://fatagnus.com/unrolling-your-loop-for-better-performance-
in-javascript/) has a better variation on the technique. In any case I would
not bother with any of this without careful profiling in different browsers.
In particular a lot of them have JIT, and I would expect JIT to automatically
optimize some of this stuff. (Either now or in the future.)

------
weeksie
If you're really having performance problems that will be fixed like that then
why not use Duff's Device? It's (and this is sure sayin' something) easier to
read than that.

~~~
saurik
Because Duff's device involves a switch outside a while with cases inside,
syntax that is not allowed by JavaScript (which carefully defines a switch to
consist of case clauses, each of which posessing a statement list). That said,
you could still do something at least reasomably similar inside of the while
(with an offset that you reset in the loop increment expression).

