alt Hacker News> WebAssembly has a sandbox and was designed for untrusted code.
So does JavaScript.
> It's almost impossible to statically reason about JS code, and so browsers need a ton of error prone dynamic security infrastructure to protect themselves from guest JS code.
They have that infrastructure because JS has access to the browser's API.
If you tried to redesign all of the web APIs in a way that exposes them to WebAssembly, you'd have an even harder time than exposing those APIs to JS, because:
- You'd still have all of the security troubles. The security troubles come from having to expose API that can be called adversarially and can pass you adversarial data.
- You'd also have the impedence mismatch that the browser is reasoning in terms of objects in a DOM, and WebAssembly is a bunch of integers.
> There are dynamic languages, like JS/Python that can compile to wasm.
If you compile them to linear memory wasm instead of just running directly in JS then you lose the ability to do coordinated garbage collection with the DOM.
If you compile them to GC wasm instead of running directly in JS then you're just adding unnecessary overheads for no upside.
> Also I don't see how dynamic typing is required to have API evolution and compt.
Because for example if a browser changes the type of something that happens to be unused, or removes something that happens to be unused, it only breaks actual users at time of use, not potential users at time of load.
> Plenty of platforms have static typed languages and evolve their API's in backwards compatible ways.
We're talking about the browser, which is a particular platform. Not all platforms are the same.
The largest comparable platform is OSes based on C ABI, which rely on a "kind" of dynamic typing (stringly typed, basically - function names in a global namespace plus argument passing ABIs that allow you to mismatch function signature and get away with it.
> The first major language for WebAssembly was C++, which is object oriented.
But the object orientation is lost once you compile to wasm. Wasm's object model when you compile C++ to it is an array of bytes.
> To be fair, there are a lot of challenges to making WebAssembly first class on the Web. I just don't think these issues get to the heart of the problem.
Then what's your excuse for why wasm, despite years of investment, is a dud on the web?
Replies
> Then what's your excuse for why wasm, despite years of investment, is a dud on the web?
It's not really a dud on the web. It sees a ton of use in bringing heavier experiences to the browser (i.e Figma, the Unity player, and so on).
Where it is currently fairly painful is in writing traditional websites, given all the glue code required to interact with the DOM - exactly what these folks are trying to solve.
> Because for example if a browser changes the type of something that happens to be unused, or removes something that happens to be unused, it only breaks actual users at time of use, not potential users at time of load.
I don't understand this objection. If you compile code that doesn't call a function, and then put that artifact on a server and send it to a browser, how is it broken when that function is removed?
> If you compile them to GC wasm instead of running directly in JS then you're just adding unnecessary overheads for no upside
Language portability is a big feature. There's a lot of code that's not JS out there. And JS isn't a great compilation target for a lot of languages. Google switched to compiling Java to Wasm-GC instead of JS and got a lot of memory/speed improvements.
> Because for example if a browser changes the type of something that happens to be unused, or removes something that happens to be unused, it only breaks actual users at time of use, not potential users at time of load. > The largest comparable platform is OSes based on C ABI, which rely on a "kind" of dynamic typing (stringly typed, basically - function names in a global namespace plus argument passing ABIs that allow you to mismatch function signature and get away with it.
I don't think any Web API exposed directly to Wasm would have a single fixed ABI for that reason. We'd need to have the user request a type signature (through the import), and have the browser maximally try and satisfy the import using coercions that respect API evolution and compat. This is what Web IDL/JS does, and I don't see why we couldn't have that in Wasm too.
> Then what's your excuse for why wasm, despite years of investment, is a dud on the web?
Wasm is not a dud on the web. Almost 6% of page loads use wasm [1]. It's used in a bunch of major applications and libraries.
[1] https://chromestatus.com/metrics/feature/timeline/popularity...
I still think we can do better though. Wasm is way too complicated to use today. So users of wasm today are experts who either (a) really need the performance or (b) really need cross platform code. So much that they're willing to put up with the rough edges.
And so far, most investment has been to improve the performance or bootstrap new languages. Which is great, but if the devex isn't improved, there won't be mass adoption.