component-model VS exception-handling

I don't think that's a very good goal. Jettisoning the DOM means jettisoning accessibility and being able to leverage everything that the browser gives you out-of-the-box. You have to render to a canvas and build everything from scratch. I think Wasm is great for supplementing a JS app, not replacing it (e.g. using a Wasm module to do some calculations in a Worker). I like to use the right tool for the job, and trying to use something other than JS to build a web app just seems a little janky to me.

At one point, there was a Host Bindings proposal that would enable you to do DOM manipulation (it looks like it was archived and moved to the Component Model spec [1]). That would probably be the ideal way to avoid as much JS as possible. However, browser vendors have been heavily optimizing their JS runtimes, and in some cases, Wasm may actually be slower than JS.

I've been following Wasm's progress for several years, which has been slow, but steady. Ironically, I think the web is actually the worst place to use it. There's so much cool non-web stuff being done with it and I'm more interested to see where that goes.

[1] https://github.com/WebAssembly/component-model?tab=readme-ov...

Well the great thing about WebAssembly is that you can port QT or anything else to be at a layer below -- thanks to WebAssembly Interface Types[0] and the Component Model specification that works underneath that.

To over-simplify, the Component Model manages language interop, and WIT constrains the boundaries with interfaces.

IMO the problem here is defining a 90% solution for most window, tab, button, etc management, then building embeddings in QT, Flutter/Skia, and other lower level engines. Getting a good cross-platform way of doing data passing, triggering re-renders, serializing window state is probably the meat of the interesting work.

On top of that, you really need great UX. This is normally where projects fall short -- why should I use this solution instead of something like Tauri[2] which is excellent or Electron?

[0]: https://github.com/WebAssembly/component-model/blob/main/des...

[1]: https://github.com/WebAssembly/component-model/blob/main/des...

[2]: https://tauri.app/

While I don't necessarily agree with the unnecessary, unsupported casual, & cheap contempt culture here ("unshackle the web from the mess that is JavaScript", "places that don't really need these problems to be solved")...

WebAssembly component-model is being developed to allow referring to and passing complex objects between different modules and the outside world, by establishing WebAssembly Interface Types (WIT). It's basically a ABI layer for wasm. This is a pre-requisite for host-object bridging, bringing in things like DOM elements.

Long running effort, but it's hard work and there's just not that many hands available for this deep work. Some assorted links with more: https://github.com/WebAssembly/component-model https://www.fermyon.com/blog/webassembly-component-model https://thenewstack.io/can-webassembly-get-its-act-together-...

It's just hard work, it's happening. And I think the advantages Andy talks to here illuminate very real reasons why this tech can be useful broadly. The ability to have plugins to a system that can be safely sandboxed is a huge win. That it's in any language allows much wider ecosystem of interests to participate, versus everyone interested in extending your work also having to be a java or c++ or rust developer.

A. Sure, but it isn't sufficiently beneficial for the cost.

B. WebAssembly is immature for developing a plugin system because of the lack of a sufficient ABI: https://github.com/WebAssembly/component-model

C. There aren't any other languages that meet the criteria. Lua was a no-go from the start. The maintainers did not like the language, and it necessitated adding more C code to Helix which could complicate building even further. https://github.com/helix-editor/helix/discussions/3806#discu...

AFAIK GC is irrelevant for "direct DOM access", you would rather want to hop into the following rabbit hole:

- reference types: https://github.com/WebAssembly/reference-types/blob/master/p...

- interface types (inactive): https://github.com/WebAssembly/interface-types/blob/main/pro...

- component model: https://github.com/WebAssembly/component-model

If this looks like a mess, that's because it is. Compared to that, the current solution to go through a Javascript shim doesn't look too bad IMHO.

The wasm idl (called WIT) is actively being worked on here: https://github.com/WebAssembly/component-model/blob/main/des...

Being able to access DOM is definitely an objective. It's just taking a lot longer than folks guessed to build a modular wasm ABI.

The WASM Component Model

https://github.com/WebAssembly/component-model

Take a look at the python abi to see what the structure looks like for calling into components https://github.com/WebAssembly/component-model/tree/main/design/mvp/canonical-abi

Interesting article, thanks!

Notes on the issues mentioned there:

* The need for a manual shadow stack: This is fixed in WasmGC (in the same way it works in JS, as the link mentions).

* Lack of try-catch: This is fixed by the Wasm exception handling proposal, which has already shipped in browsers, https://github.com/WebAssembly/exception-handling/blob/main/...

* Null checks: Mostly fixed by WasmGC. The spec defines non-nullable local types, and VMs can use the techniques the article mentions to optimize them using signals (Wizard does, for example).

* Class initialization: This is a difficult problem, as the article says. J2Wasm and Binaryen are working to optimize it through static analysis at the toolchain level. Here is a recent PR I wrote that makes progress there: https://github.com/WebAssembly/binaryen/pull/6061

* The vtable overhead issue the article mentions may be a problem. I'm not aware of good measurements on it, through. There are some ideas on post-MVP solutions for method dispatch that might help, but nothing concrete yet.

* Checks for null and trapping: There has been discussion of variants on the GC instructions that throw instead of trap. Measurements, however, have not shown it to be a big problem atm, so it is low priority.

The author is right that stack walking, signals, and memory control are important areas that could help here.

Overall with WasmGC and exceptions we are in a pretty good place for Java as emitted by J2Wasm today: it is usually faster than J2CL which compiles Java to JavaScript. But there is definitely room for improvement.

It uses https://github.com/WebAssembly/exception-handling/blob/master/proposals/exception-handling/Exceptions.md which is actually supported by all major browsers already.

Yep, you're right. It's also more than just the DOM, it's web APIs in general, such as fetch, audio, webgl/webgpu, etc. WASM still needs GC, exceptions, and WASI to be able to fully interop with any host without any of the current limitations. This'll take a few years. I'm looking forward to the future in which I will be shipping WASM-only web apps to my users.

Its a part of the wasm plan to support gc https://github.com/WebAssembly/gc exceptions https://github.com/WebAssembly/exception-handling

As of Node.js 17, the v8 JavaScript engine has been updated to v9.5. The changes in this release are primarily aimed at expanding internationalization for dates and calendars as well as for the output of time zones. It also implements the WebAssembly Exception Handling proposal, designed to reduce overhead compared to current JavaScript-based workarounds.

Agreed, although at some point in a not very far feature most of those missing features will resolved. So in my mind is just a matter of time. The Wasm Community group is doing an awesome work on that :)

Here are a few examples of what needs move forward in Wasm:

* [1] Wasm Exceptions Handling: Right now Wasm is missing a way to handle exceptions natively (C++ programs can only compile to Wasm using the asyncify or longjmp/setjmp tricks via Js try/catch)

* [2] Wasm GC: Wasm Binary files are quite big (specially in interpreted languages). This is partially caused by the GC being included in the Binary itself. The GC proposal will solve this while also providing faster execution.

* [3] Wasm 64-bit Memory: currently Wasm can only operate with 32-bit data. In some contexts you may want you operate with more than 4GB of memory (for example, when operating over terabytes of data). The 64-bit memory proposal will solve that.

[1]: https://github.com/WebAssembly/exception-handling