Are frozen Objects faster ?

Andrea Giammarchi andrea.giammarchi at
Fri Feb 15 12:47:15 PST 2013

not sure I follow here ... I did ask if Object.freeze was faster and why,
if not, 'cause faster is what I would expect after a probably slower
operation as freeze could be.

Aymeric yes, that was unfortunate, also I don't understand all these
different behaviors but point is, I think you can extend in Chrome, you
cannot in Firefox and no idea why this choice (bu tI understand the
implementation of static, fixed, type/shape)

So, it looks like is planned, but nobody knows when? Well, that's better
than nothing :-)

On Fri, Feb 15, 2013 at 4:09 AM, Alex Russell <slightlyoff at>wrote:

> On Thursday, February 14, 2013, Andreas Rossberg wrote:
>> On 14 February 2013 19:26, Herby Vojčík <herby at> wrote:
>> > I meant "de facto". People wanting to remove property bar from foo do
>> not
>> > write `delete` anymore; they (at least some significant subset)
>> have
>> > learned to write ` = null;` or ` = undefined;`. The
>> reason is
>> > perf - `delete` deoptimized hidden classes.
>> And with ES6, those people will hopefully realise that for those
>> cases, using a Map is a cleaner alternative anyway.
> I think it's worth noting here that *of course* older features have seen
> heavier optimization. I honestly expect that the Map type will start much
> slower than it will eventually end up being, perhaps not in V8, but
> elsewhere. But slow and available often beats unavailable and/or
> non-standard. It's a complicated story to tell end-users, but anything else
> is misleading.
> One hopes that any new feature we that gets wide implementation and is not
> explicitly performance oriented pays for itself on a semantic basis. Such
> features find their natural users prior to the optimization foot race
> kicking off, and there's nothing bad about any of that. The ideal world
> (that freeze() is now a poster child for) looks roughly like:
> // Standard written, implementations arrive (not in that order)
> // ...time passes...
> Hooray! New features!
> // ...time passes...
> // Users realize optimization is uneven
> Boo! They're slow! // Said without any sense of JS perf history
> // ...time passes...
> // Features optimized
> Yay! They're fast!
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