I’ve been wondering about this for a while and haven’t really found a great answer for it. From what I understand, WASM is:
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Faster than JavaScript
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Has a smaller file size
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Can be compiled to from pretty much any programming language
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Can be used outside of the browser easier thanks to WASI
So why aren’t most websites starting to try replacing (most) JS with WASM now that it’s supported by every major browser? The most compelling argument I heard is that WASM can’t manipulate the DOM and a lot of people don’t want to deal with gluing JS code to it, but aside from that, is there something I’m missing?
But other than that, Mrs. Lincoln, how was the play?
You’ve gotten several other answers that are true and correct - the pain of implementation at this point is greater than the pain points that WASM solves. But this is also a non trivial one - most of what Javascript should be doing on a webpage is DOM manipulation.
At some point, WASM will either come out with a killer feature/killer app/use case that Javascript (and all the libraries/frameworks out there) hasn’t figured out how to handle, and it will establish a niche (besides “Javascript is sort of a dumb language let’s get rid of it”), and depending on the use case, you might see some of the 17.4 million (estimated) Javascript developers chuck it for…what? Rust? Kotlin? C? C#? But the switching costs are non-trivial - and frankly, especially if you still have to write Javascript in order to manipulate the DOM…well, what are we solving for?
If you’re writing a web app where one of the WASM languages gives you a real competitive advantage, I’d say that’s your use case right there. But since most web applications are basically strings of api calls looped together to dump data from the backend into a browser, it’s hard to picture wider adoption. I’ve been wrong before, though.
I’m amazed at how much you described in a single sentence there
I’d imagine one of those killer features is using a language with a solid standard library. Npm dependencies are notoriously complex because js as a language is missing basic functionality that is standard in other languages. Just a few years ago the Internet broke because “pad left” was pulled by it’s maintainer, that simply doesn’t happen in other languages
From a maintenance perspective npm is a nightmare. From a security perspective it is worse. Being able to build your entire website using a language that eliminates most dependencies, and the ones you take on don’t pull in a zillion dependencies either, is absolutely a killer feature
Of course that isn’t the full story and using js still has it’s advantages as people have already pointed out. If wasm closes the gap in those areas then it would absolutely be worth the switch
Even if WASM gets some amazing feature, like super-fast DOM manipulation, it would still be used via API from JavaScript. WASM is a subset of JavaScript that mainly consists of low level operations. It’s not exactly nice for writing code. It’s like assembler in this respect — very fast, very efficient, but we still tend to prefer a higher level language.
How is WebAssembly a subset of JavaScript? Aren’t you confusing it with asm.js?
He meant it as “wasm will be invoked by javascript” and not the other way around.
I don’t know what you mean by WASM being a subset of javascript (maybe you mean AssemblyScript?) You can still program in higher level languages like C and have it compile into WASM as one would compile C to assembly.