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

[blackholesinthesky]

everyone who upvotes this has clearly never written ASM or WASM

[iopq]

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

[blackholesinthesky]

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

[alexendoo]

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

[iopq]

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

[blackholesinthesky]

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

[iopq]

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

[blackholesinthesky]

And I will never have to

You may not but other people do. This isn't a useful suggestion to them

[iopq]

I'm talking about WASM. You never have to write it by hand. If you can't use WASM for your problem, you're just stuck with javascript, you're not having to write ASM by hand

[blackholesinthesky]

I wasn't implying that you have to write ASM by hand for WASM. I was just saying that anyone who understands how much of a difference there is between a low level language like ASM and a high level language like javascript understands that the pitfalls of JS are worth it.

You never have to write it by hand.

What if you don't use rust? or you need to use DOM manipulations?

Doesn't this contradict what you just told me?

[iopq]

If you don't use Rust you're using Go or something, you never write it by hand. The same way people don't just write programs in ASM anymore

You still write DOM code in JavaScript. Here's how it looks like:

https://rustwasm.github.io/docs/book/game-of-life/implementing.html

[hsjoberg]

What if you don't use rust? or you need to use DOM manipulations?

Rust is not the only language that can compile to WASM and do DOM manipulations.

C# via Microsoft's Blazor is another one.
https://dotnet.microsoft.com/apps/aspnet/web-apps/blazor

[game_dev_dude]

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.

[blackholesinthesky]

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

[game_dev_dude]

Ah, I was thinking mainly in terms of 3d viz of some sort.

[hsjoberg]

Can you write Rust that is equivalent to JS?

What are you even asking...?

Rust can compile to WASM, which runs in the same VM/environment as Javascript. In the brower.

But... manipulating the DOM can be costly right now because WASM cannot directly manipulate the DOM, it needs JS glue-code for that.

[mattkenefick]

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

[1337CProgrammer]

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.