Earlier quoted context omitted.
Also, JS is a more suitable target for most managed languages like clojure, typescript, elm, etc.
Well... two of 3 of the languages you provided as example were designed to be transpiled to javascript. I doubt JS is a more suitable target for other languages than an IR like wasm which is being designed to be a compiler target.
Even the WebAssembly authors seem to agree that it's not foremost a managed language compile target - The Overview text from http://webassembly.org/ says "Wasm is designed as a portable target for compilation of high-level languages like C/C++/Rust, enabling deployment on the web for client and server applications."