How to Reverse JavaScript Shellcode:?

With more and more exploits being written in JavaScript, even some 0-day, there is a need to be able to reverse exploits written in JavaScript beyond de-obfuscation. I spent some time this weekend searching Google for a simple way to reverse JavaScript shellcode to assembly. I know people do it all the time. It's hardly rocket science. Yet, I didn't find any good walk-throughs on how to