the main page/javascript code to de-obfuscate

use manual helpers to produce evaluation items, like those on the right panel

These manually created evaluations will be executed in the page context. You use them to help R.E. process to simplify the source you have.

There are actually only two types of evaluations you can setup:

function: in source calls to given functions will be replaced with their results

regexp: you use regexp to specify arbitrary expressions from source which would evaluated and replaced