Experimental implementation of Object.observe & JS Utility library now available

Tab Atkins Jr. jackalmage at gmail.com
Fri Aug 17 18:52:53 PDT 2012


On Fri, Aug 17, 2012 at 6:49 PM, Brendan Eich <brendan at mozilla.org> wrote:
> All praise to Raf et al., my concern is that something synchronous, plus
> event loop concurrency and setImmediate, would suffice to bootstrap the
> rather more elaborate proposal on top of the simpler O.p.watch like
> fundament.
>
> This is not to say we shouldn't standardize higher-level APIs, and instead
> push that off on library authors to write, and users to download. There's a
> delicate balance here. We often screw up higher-level abstractions in
> annoying ways, but perhaps that risk is worth taking.
>
> What I'm really getting at is this: why not expose the synchronous primitive
> and e.l.c. building blocks as well?

For the same reason we're killing MutationEvents, rather than just
promoting MutationObservers as a better alternative - synchronous
change notifications slow things down considerably, and they're *very*
prone to making the browser crashy. Get the slightest thing wrong in
your implementation, and suddenly the user is holding onto a null
pointer.

~TJ


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