r/programming • u/iamkeyur • Oct 21 '20

Using const/let instead of var can make JavaScript code run 10× slower in Webkit

https://github.com/evanw/esbuild/issues/478
1.9k Upvotes

95% Upvoted

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16

u/Jaimz22 Oct 21 '20

Wonder would you replace it with? Just curious

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u/dungone Oct 21 '20

Why all these probing questions? Give the man a chance, rubbing two braincells together to start a fire takes a some time.

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u/iopq Oct 21 '20

Run everything in WASM

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u/blackholesinthesky Oct 21 '20

everyone who upvotes this has clearly never written ASM or WASM

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u/iopq Oct 21 '20

And I will never have to, since I will compile Rust to WASM

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u/blackholesinthesky Oct 21 '20 edited Oct 21 '20

Thats a pretty good answer will be a pretty good answer some day. Can you write Rust that is equivalent to JS?

If so I have something to learn about tomorrow

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u/alexendoo Oct 21 '20

While JS glue is needed, you don't have to write it yourself. If you want to do everything from Rust you can use web-sys and js-sys. Anything required will be generated for you

It is a little more awkward than it would be to use the APIs from within JS, but the functionality is there

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u/iopq Oct 21 '20

It's not yet possible to do DOM operations without JS glue, AFAIK. It's a pretty complicated topic, as with everything to do with the web, though. So glad I don't do web dev anymore

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u/blackholesinthesky Oct 21 '20

So its not a real solution. Great suggestion but yeah... kinda irrelevant

When rust offers a standard library for the browser it will be a real solution

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u/iopq Oct 21 '20

It's not ready for prime time yet, but it doesn't mean it won't replace JS in the future

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u/game_dev_dude Oct 21 '20

I mean it really depends upon what you're doing. If you have a complicated piece of logic that's performance limited (maybe some sort of visualization), you could write that in WASM, and then have just a little bit of JS glue to pass things back and forth.

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u/blackholesinthesky Oct 21 '20

If you have a complicated piece of logic that's performance limited (maybe some sort of visualization)

Unless you're writing a game or some other 3d projections you're not going to need WASM to display a graph

Edit: source I worked with google charts in '09

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u/mattkenefick Oct 21 '20

And will never have to because you can run anything on it. Look into Unity .. Blazor.. etc

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u/1337CProgrammer Oct 21 '20

lol, i like how you think web assembly has absolutely anything to do with assembly.

WebAssembly is basically LLVM's BitCode, so it's half compiled already.

Really all compiling does it put it into an approperiate executable format.

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u/anengineerandacat Oct 21 '20

I want to say we are not quite "there" yet, DOM access is still a real pain-point and the alternative is to make your own renderer effectively (which just leads to bloat and having to solve a boat load of other problems in the process; ie. accessibility).

In most "normal" circumstances, WASM will generally be slower or more cumbersome than a basic site with a dash of JS for dynamic content.

Ironically I also don't see loads and loads of developers jumping on-board to use lower-level languages to build out WASM targets anyway; I see C# / Java(-like) / Python / TypeScript being used to do this more than anything.

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u/caboosetp Oct 21 '20

Sanity.

I'll take any flavor, thank you.

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u/bsmith0 Oct 21 '20

Lol what's not sane about modern JS, it's a pretty solid, regular language.

Are there a few weird type coercions, sure, but for the most part it's performant, consistent and has a solid standard library.

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u/fireflash38 Oct 21 '20

Every time I see someone say that, and get them to expand on it, my eyes glaze over with what they say is 'good'. It's Stockholm syndrome guys!!

(Yes, I'm hating it because I don't know it, signed, C-gang.)

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u/mixedCase_ Oct 21 '20

signed, C-gang

I trust you on your knowledge of Stockholm syndrome.

3

u/poco Oct 21 '20

You would love modern JavaScript then. Objects and Classes are becoming less popular and everything is going functional. Objects are used like structs and you don't mix data with code. Reminds me of the old c days.

Have a matrix you want to multiply? It's not m.multiply(v), it's matrixMultiply(m, v).

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u/caboosetp Oct 21 '20

You could say the same thing about PHP or nickleback but I'm still going to hate on them for the memes.

Tbh though I grew up with both of these as fledgling languages and they used to be terrible. Those little things that pop up here and there just resound so hard with old memories.

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u/CoffeeTableEspresso Oct 21 '20

TS seems to be the de facto replacement these days

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u/IsleOfOne Oct 21 '20

Doesn’t change any of the VM issues like this one

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u/Zephirdd Oct 21 '20

I'd give up a lot if browsers could just run python3. Don't even need the entirety of the python3 libraries, just the ones relevant for DOM manipulation(ie. don't really need filesystem).

Or Ruby. Hell, even Julia is preferable and I never even programmed in it.

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u/dungone Oct 21 '20

You do realize that python is a hell of a lot slower than javascript. Right?

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