Wasm can't do anything JS couldn't do already.

yjbanov · on March 3, 2021

There are a few things that WASM can do that JS can't (at least not now):

- Memory management without GC - Unboxed data structures - SIMD - Shared-memory multi-threading - Precompiled snapshots (does not need to be recompiled on page reload)

hajile · on March 4, 2021

Bytecode caching has been a browser feature for years[0]

JS has atomics and shared memory arrays which also basically bypass garbage collection [1]

JS had working simd.js implementations in both Firefox and Chrome until they were pulled in favor of WASM

[0] https://v8.dev/blog/code-caching-for-devs

[1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...

[2] https://github.com/tc39/ecmascript_simd

https://blog.mozilla.org/javascript/2015/03/10/state-of-simd...

https://01.org/blogs/2014/bringing-simd-javascript

dagmx · on March 4, 2021

I should clarify, in the context of the reply I was referring to security. Wasm is inherently as secure as JavaScript.

AlchemistCamp · on March 4, 2021

It can do integers.

hajile · on March 4, 2021

BigInt landed in ES2020 and has been supported in something like the last 10-20 versions of Chrome and Firefox, so no huge worries about using it (the "current" browser without support is IE11).

The `123|0` type hint is also recognized and implemented by most browsers too. It forces a 31-bit integer on most platforms (and can offer a significant performance boosts if you're running a tight algorithm).

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...

ttt0 · on March 3, 2021

What JS can do is already bad enough.