I'm not the parent poster, but I think it's quite possible we see JavaScript, TypeScript, and maybe even CoffeeScript and ActionScript frontends that target WAS

I'm not the parent poster, but I think it's quite possible we see JavaScript, TypeScript, and maybe even CoffeeScript and ActionScript frontends that target WASM backends. Right now it's possible to support subsets of the languages. As WASM is fleshed out and tools like Nectar/NectarJS and wasm-bindgen improve the workflow might change more than the source language. Mostly unrelated to JavaScript, there's also an effort called JWebAssembly which strives to translate JVM bytecode to WASM's binary (.wasm) or textual (.wat) format. So WASM apps could be written fine in Scala, Clojure, Kotlin, JRuby, or any other JVM language. I think where WASM definitely replaces JavaScript is distribution over the net to browsers for heavy web applications and in Node apps. It's just way more efficient. JS might still have a place for a little bit or bauble on some sites that are mostly static HTML, but things that use huge stacks of JS libraries will have those precompiled to WASM for distribution.