const evenItems = arr = arr.filter((_, index) => index % 2 === 0);
Returns an array which contains every even item of the ...
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Or you use the fastest possible version:
Hey!
thank you for taking the time to contribute, I put both functions to the performance benchmark on hasty and I'm going to update the article with your suggestion!
Cheers!
+1 for this. I'll always prefer legible over performant unless dealing with code that absolutely requires performance. 99% of the time I'm dealing with small datasets so it isn't necessary. And as you've said below, v8 optimises a lot of these convenience methods.
I would have thought filter was indeed slower, but not according to this.
It is one of the cases where performance really depends on the browser / javascript engine.
Agreed.
I tested it w/ Chrome, on Mac & Linux. Not sure how Safari / Firefox results may vary.
Appreciate the discussion. Going to use the filter version as I expect the other browsers / javascript engines to catch up in microoptimisations.
Then at least use
&instead of%if you care about performance. That difference can't be microoptimized, because the modulo requires float point handling, whereas the binary operation runs directly on the CPU.Hi Luke,
yes you are right :D Here is the updated benchmark on hasty - filter is much slower for me.
No, it isn't faster. Not sure what's wrong with your machine, but it's about 20-30% slower on any machine I tested it on.
I just ran that test and for was 20% faster on current Chrome.
Hi Luke,
you are right filter is more intuitive, but it is actually slower for me.
Cheers!