Comment by Leszek
4 days ago
The complex parts of JavaScript are the semantics, not the syntax. You could reasonably easily spec a bytecode for JS to get rid of the syntax part, but nothing would change in the complexity (almost all modern engines parse to bytecode as the first step and operate on bytecode from then on).
If you wanted to implement JS in wasm, you'd either need a bunch of wasm extensions for JS semantics (dynamic object shape, prototypal inheritance, etc), or you'd need to implement them in wasm from scratch and basically ship a JS runtime written in wasm. Either that, or you need to change the language, which means de facto adding a new language since the old JS still has to stick around for old pages.
I admit I don't have depth of knowledge with how JS and Wasm work behind the scenes, but you can already compile JS to wasm. Forgive the ignorance, but what am I missing here? When you compile JS to wasm, aren't the semantics and language behaviors already addressed?
My understanding was that things like DOM manipulation APIs would need to be (and are) exposed to the WASM runtime so that the JS-to-WASM compiler could do all the right bytecode "linking".
My idea is that if JS itself was require to in WASM, and native JS support didn't exist, the complexity in browsers would be reduced dramatically. And developers will be free to use different languages. Browsers will focus on APIs instead of language semantics. no more V8!
You can't currently "compile JS to Wasm", you can compile a JS engine (likely written in C++) to Wasm and run JS inside that (almost certainly at lower speed). So instead of "no more V8", it's closer to "ship V8 as part of the website, instead of part of the browser". Exposing DOM APIs to Wasm is a completely different question, though even those would actually have to be new APIs with a new API design that works for Wasm, since the existing DOM APIs are effectively defined in terms of JS objects being passed around.
I didn't know this, thanks for explaining. If DOM APIs could be reworked for wasm support, and JS can work with those APIs, that would suffice. It won't get sites off normal JS any time soon. As far as speed, is it an optimization problem? I'd think just running bytecode is faster than interpreting a script. It doesn't need to be backwards compatible with existing JS code, it just needs to be possible to write front end code in JS for WASM. Migrating to the new approach could be similar to migrating away from Flash, ActiveX and Applets, but at a much larger scale.
10-20 years from now, is it really ok to be stuck with JS and CSS? The complexity is compounding, ever newer webapi's get encoded as JS APIs, and the dependency mess will only increase. Browsers are about as complex in some ways as an operating system. If we think about the world in terms of decades, what is the plan? This is a very serious issue, because of how much the world depends on browser tech, and effectively, Google is the arbiter and overseer of that technology. I don't think this will work out well, unless there is some timely foresight in the architecture.