Are frozen Objects faster ?
herby at mailbox.sk
Thu Feb 14 10:26:54 PST 2013
Mark S. Miller wrote:
> On Thu, Feb 14, 2013 at 10:09 AM, Herby Vojčík <herby at mailbox.sk
> <mailto:herby at mailbox.sk>> wrote:
> Kevin Gadd wrote:
> Frozen and sealed objects are both dramatically slower in most JS
> engines I've tested. In the ones where they're not dramatically
> they are never faster.
> The last time I asked on the mozilla and v8 bug trackers I was
> informed that there is no plan to optimize for these features
> and that
> the design of the respective JS engines would make such
> difficult anyway.
> (I find this extremely unfortunate.)
> I, on the other hand, find it fortunate. Otherwise, some people
> would prematurely freeze objects to gain speed. It would be same
> <del>disaster</del> akwardness as v8 did with removing `delete` in
> favour of `= null`.
> What are you referring to? What 'delete' was removed?
I meant "de facto". People wanting to remove property bar from foo do
not write `delete foo.bar` anymore; they (at least some significant
subset) have learned to write `foo.bar = null;` or `foo.bar =
undefined;`. The reason is perf - `delete` deoptimized hidden classes.
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