That sounds like a major V8 bug that [should be reported][1] - there should be zero performance difference between an arrow function and a normal ES5 function. They're completely equivalent apart from ES5 functions being constructible and arrow functions forming a closure around the current call context. In particular, I'd expect them to be *faster*, not slower.
[1]: https://bugs.chromium.org/p/v8/issues/list ----- Isiah Meadows [email protected] Looking for web consulting? Or a new website? Send me an email and we can get started. www.isiahmeadows.com On Sun, Nov 12, 2017 at 5:45 AM, J Decker <[email protected]> wrote: > > > On Sun, Nov 12, 2017 at 2:14 AM, T.J. Crowder > <[email protected]> wrote: >> >> On Sun, Nov 12, 2017 at 9:56 AM, J Decker <[email protected]> wrote: >> > Arrow functions passed as callback to Node.js addons execute 20% >> > slower than regular 'function()' functions. >> >> **Wow**. Is that written up somewhere one could read more? >> >> When you say "Node.js addon," are you excluding built-in Node APIs? > > > Basically it was an empty function I was calling with some simple parameters > It was only something I found through experimentation. It really has > nothing to do with NodeJS other than it was an addon, it was just > interacting with the V8 engine. > > Writing file... > Wrote in 199 .. reading... > ()=>{} Read in ... 300000 3394 > function(){} Read in ... 300000 2690 > > https://github.com/d3x0r/sack.vfs/blob/master/tests/largeStreamtest.js#L15 > and line 18 is the other one. > In the function I just increment a counter.... 126% or 79.25% ...but then > there is quite a bit of overhead in my library to parse the JSON. that's > quite a nested object > `{\"a${i}\":{\"b${i}\":{\"c${i}\":{\"d${i}\":123}}}}` > -------------- > Hmm... changed the file that was being generated to just a simple string, > and the timings were closer (but was less than 1 second run) so I added some > generation counts and ran the tests in various orders... and I guess maybe > it was because of other factors that coincidentally showed as ()=>{} being > slower than function(){} > > function(){} Read in ... 100000 958 > ()=>{} Read in ... 100000 906 > ()=>{} Read in ... 100000 784 > function(){} Read in ... 100000 783 > ()=>{} Read in ... 100000 924 > function(){} Read in ... 100000 779 > function(){} Read in ... 100000 881 > ()=>{} Read in ... 100000 805 > > then just reversed the two tests in the original script and the timing > stayed the same in-order... but then would show function() as being the > slower one. > > My Bad; thanx for asking about that though I would have been stuck with that > misconception for a long time. > > >> >> -- T.J. Crowder > > > > _______________________________________________ > 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
