JavaScript Array.push is 945x faster than Array.concat

Re:JavaScript Array.push is 945x faster than Array.concat by TAForObvReasons on Thursday May 23, 2019 @01:18PM (#19993722)

The issue is that the community 5-10 years ago heavily favored "pure" approaches like Array#concat rather than mutations like Array#push. So a whole new generation of developers were taught to avoid the functions at all costs. "never use push" is a common mantra in JS circles, and developers favored making a copy of an array even if that array was used nowhere else (where push would've been the appropriate choice) Maybe we're seeing a push back towards performance over purity?

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Re:JavaScript Array.push is 945x faster than Array.concat by ng12 on Thursday May 23, 2019 @02:09PM (#19994296)

> Maybe we're seeing a push back towards performance over purity?

No, because performance is generally not a huge concern on the front-end. I'm not applying ML strategies to hundreds of thousands of data points, I'm trying to render 10 elements instead of 9. Performance is so rarely a concern that I'd always err on the side cleaner code than hyper-performant code. This stuff isn't even worth thinking about.

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Re:JavaScript Array.push is 945x faster than Array.concat by MiddleEndian on Thursday May 23, 2019 @11:22PM (#19998192)

>performance is generally not a huge concern on the front-end

Everyone who has ever used a web app already knows this unfortunately.

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Re:JavaScript Array.push is 945x faster than Array.concat by ng12 on Friday May 24, 2019 @10:54AM (#20002161)

You're like the third person to make this snarky comment in this thread. I promise you the JavaScript runtime is not the bottleneck.

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Re:JavaScript Array.push is 945x faster than Array.concat by EForEndeavour on Thursday May 23, 2019 @02:50PM (#19994688)

Javascript isn't just a frontend language though, is it?

> I'm not applying ML strategies to hundreds of thousands of data points

Maybe you aren't, but the folks over at tensorflow.js [1] certainly are, as well as Andrej Karpathy's ConvnetJS [2].

[1] https://www.tensorflow.org/js [2] https://cs.stanford.edu/people/karpathy/convnetjs/demo/class...

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Re:JavaScript Array.push is 945x faster than Array.concat by ng12 on Thursday May 23, 2019 @03:06PM (#19994865)

Which is why I specified I was talking about the front-end.

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Re:JavaScript Array.push is 945x faster than Array.concat by EForEndeavour on Friday May 24, 2019 @12:10PM (#20002978)

There's plenty of demand for and work on frontend JS performance as well, e.g, https://greensock.com/

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Re:JavaScript Array.push is 945x faster than Array.concat by ng12 on Friday May 24, 2019 @01:34PM (#20003663)

You're being pedantic -- I'm not saying that there performance-critical JS code doesn't exist, I'm saying that the push for readability over performance isn't going anywhere.

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Re:JavaScript Array.push is 945x faster than Array.concat by apk-d on Thursday May 23, 2019 @06:07PM (#19996509)

> This stuff isn't even worth thinking about.

If more front-end developers have this mindset, I'm beginning to understand how the web (and the desktop, via electron and such) has become the embarrassingly slow and unusable mess that it is nowadays.

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Re:JavaScript Array.push is 945x faster than Array.concat by ng12 on Thursday May 23, 2019 @06:09PM (#19996533)

I can promise you the JavaScript runtime is not the cause of whatever "slow and unusable mess" you've experienced.

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Re:JavaScript Array.push is 945x faster than Array.concat by pdimitar on Saturday May 25, 2019 @07:12AM (#20008321)

True, but these things add up. It is definitely not a problem at one spot; make those spots 100 and the problem manifests itself very obviously.

I am a fan of expressive and readable code as well and have fully migrated to functional languages in the last 2-3 years. But I don't think in JS we have the luxury to ignore a 945x performance improvement on a very low-level building-block function. It's used in thousands of places.

So you know, I agree with your premise. As a compromise I'd make an utility that reads much better than `Array.push` but still uses it internally (if such a tool does not already exist).

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Re:JavaScript Array.push is 945x faster than Array.concat by BubRoss on Thursday May 23, 2019 @02:55PM (#19994745)

Performance might not be a concern for you, but it is your users who should be deciding.

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Re:JavaScript Array.push is 945x faster than Array.concat by ng12 on Thursday May 23, 2019 @03:04PM (#19994846)

As if my users would ever notice. Some of them are still using IE9.

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Re:JavaScript Array.push is 945x faster than Array.concat by ummonk on Thursday May 23, 2019 @03:48PM (#19995266)

Immutable.js has good functionality to allow you to batch pure operations if you don’t actually need the intermediate values.

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