I think we all know that's extremely slow and since ever. I always wondered the reason too ... in jsperf there are tons of tests about this, here yet another one just quickly created to compare the gap: http://jsperf.com/bind-is-slow
in Chrome, bind(context) without even arguments is 87% slower than a closure with call On Fri, Jul 12, 2013 at 10:09 AM, Mark S. Miller <[email protected]> wrote: > If you can manage it, most effective would be to get .bind (or any other > operation you want to be faster) into some widely quoted benchmark suite. > > > On Fri, Jul 12, 2013 at 9:46 AM, Allen Wirfs-Brock > <[email protected]>wrote: > >> you might consider ticketing performance bugs against the various >> implementations. >> >> Allen >> >> >> On Jul 10, 2013, at 9:16 AM, Claus Reinke wrote: >> >> > The TypeScript project tries to emulate arrow functions through the >> > "_this = this" pattern and keeps running into corner cases where a >> > semi-naïve renaming is not sufficient. >> > >> > I have been trying to suggest using .bind to emulate arrow functions >> > instead, but the counter-arguments are (a) .bind might not be available >> > (supporting pre-ES5 targets) and (b) .bind is slow. >> > >> > The polyfill isn't the problem, but I'm a bit shocked every time >> > someone reminds me of the performance hit for using .bind. Given >> > that a bound function has strictly more info than an unbound one, >> > I wouldn't expect that (I expected a bound function to be roughly >> > the same as an unbound function that does not use "this"). Unless >> > there is no special casing for the just-add-this case, and .bind is >> > always treated as a non-standard (meta-level) call. >> > >> > While playing with test-code, I also found that v8 does a lot better >> > than other engines when using an .apply-based .bind emulation. >> > >> > Can anyone explain what is going on with .bind, .apply and the >> > performance hits? >> > >> > The TypeScript issue is https://typescript.codeplex.com/workitem/1322 . >> > My test code (*) is attached there as "bind-for-arrows.html". >> > >> > Claus >> > http://clausreinke.github.com/ >> > >> > (*) I also tried to make a jsperf test case, but the way jsperf >> > runs the loop seems to prevent the optimization that makes >> > v8 look good for the .apply-based bind. >> > >> > _______________________________________________ >> > es-discuss mailing list >> > [email protected] >> > https://mail.mozilla.org/listinfo/es-discuss >> > >> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > > > > -- > Cheers, > --MarkM > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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