Rust and WASM for Form Validation

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.

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

> Obviously, the sample code above unwraps to high heaven, and that’s nothing something I would condone in actual production code—please do use proper error handling.

Everywhere the author used `unwrap` is a place where I would expect the program to crash if the operation fails, so I'm not sure what they imagine "proper error handling" in this case would look like. Take this snippet for example:

  let doc = window().unwrap().document().unwrap();
  let form = doc
      .get_element_by_id("login")
      .unwrap()
      .dyn_into::<HtmlFormElement>()
      .unwrap();

In javascript that looks like this:

  // or you could write nothing.  `login` is already a global variable
  let form = document.getElementById('login');

At a glance, the web-sys docs don't say, but I assume the error conditions that would trigger those `unwrap`s are:

- The `window` global is missing or the code is running outside of the browser

- The `document` global is missing

- The page has no form element with an id of "login"

I don't see a reasonable thing to do in those cases except crash.

A more general point: I find WebAssembly works best when:

- Interfacing with the DOM and web APIs is still mostly done in javascript

- The wasm binary has a narrow interface consisting of a handful of functions with careful calling conventions

- The wasm binary avoids dependencies on either third-party packages or the standard library (e.g. rust's "no_std")

- The compiled code generously uses mutable "global" variables (note: local to the wasm module instance)

The rust + wasm-bindgen + web-sys strategy feels like the exact opposite of this, which doesn't strike me as very useful unless you just want to avoid writing javascript entirely.

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.

  /^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/

Learn JavaScript.