Rust and WASM for Form Validation
16 comments
·July 4, 2025neoneye2
I have done the same, using same rust code for frontend/backend.
The UI is here https://loda-lang.org/edit/?oeis=2487
It can run from commandline for mining.
Implementation https://github.com/loda-lang/loda-rust
reactordev
Oh dear god no. Form Validation is what JavaScript was meant for. Do we really need to download >1MB wasm module so you can do a regex?
WASM should be left to things like IPC/Canvas/WebGPU stuff, not things easily done with document.querySelector
No offense, but this is using a bomb to kill a fly.
I know it says this is just a demo but people will find this and do this thinking it’s normal.
milliams
I just compiled the code provided in the article and the compiled WASM module is 22kb. Not saying that it makes it the right solution, but a 45× difference is not insignificant.
remram
But the example code doesn't do much validation. If you did want to use a regex, you would have to compile and bundle the regex crate...
littlestymaar
And what kind of form validation are you going to do with a regular expression? E-mail addresses like every other fool? (This is a the best to reject perfectly valid addresses because you baked unjustified assumptions in you regex)
madduci
Same with some JavaScript frameworks. I need to download 700kb+ JS files just to perform some fancy stuff.
jpdenford
The author said the following
> I’m using form validation as a placeholder. It shows all the crucial aspects to use WASM instead of JS, like wiring up DOM events to Rust functions, and then reacting to those events.
qoez
Once you compile it to wasm and dead code analysis is applied and notices that only a fraction of whatever libraries you're using is necessary for form validation the code tends to be a lot less than what you'd have if you used non dead code analyzed pure JS.
graypegg
Well, if we were implementing the equivalent in JS, we'd also use https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputEl... just like this. I think it would maybe be a few lines of javascript at most to do exactly what this is doing. 400ish bytes?
Of course there's always the argument that you'd add more javascript to "framework-ize" this a bit more, but the rust code is just targeting the DOM with IDs, so I don't think it's fair to compare it to any "framework-y" solution.
wasmperson
[dead]
jedisct1
Learn JavaScript.
Dioxus 0.7 comes with a set of components that cover even most of interaction with the JS side. There are great times ahead. What seems to be missing is modularizing and lazy loading of the WASM moduls to reduce initial download size (I saw some experiments). I immensely enjoy being able to use a sane language+tools for backend and frontend.