What is the best language suited for optimizing of wasm binary (other than WAT)?

I am looking into wasm to improve the performance of some numerical processing in my web application. And I read "The Art of WebAssembly" to learn about WAT.

The knowledge of WAT is very useful, but I am planning to use a higher level language than WAT when I actually replace the numerical computation process with wasm.

Currently, there are numerous options. asm.js, Emscripten(C++), Rust, Golang, and AssemblyText, etc.

I have already learned that simply replacing Javascript code with another language that can compile to wasm is not going to do much. What language is best suited in terms of "fully optimizing performance", i.e., best suited for optimizing the output of the wasm binary?

My skill set includes Java, Ruby, JS/TS, Lisp, Golang, etc., but please ignore such prerequisites. And please use something other than WAT.

If you are targeting the web then emscripten (C/C++) or AssemblyScript are likely your best bet. Sadly, the rust toolchain for targetting the web is not really maintained these days.

Whether or not you see performance gains over JS or more of function workload you have and less about about source language you choose. Workloads that are compute heavy and light on interactions with the environment (i.e. the Web platform) should be well suited to performing well under WebAssembly, so it sounds like could see some gains.