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?
Sure, you can autogenerated js bindings, but as soon as you need to start debugging or optimizing you need to understand the js that was generated for you.
I don't think so. Having played around with wasm-bindgen in rust as well as other libraries the build on top of it I have never once needed to look at or understand the generated JS code. When you need to debug or optimise things the first thing to look at is the rust code. So as it stands today I do not think you need to know JS to write code for a web frontend - at least in isolation of anything else (ie teams, existing products etc).
You will likely need to learn JS at some point when writing stuff for the web - as the JS ecosystem is so vast for web development when compared to anything else. But WASMs JS bindings are not the point you will need to know it for.