Original source
Attempt method hashing and renaming for 2D canvas context WebGL canvas context AudioContext
Assume global variable is a (as in js1k shim)
Reassign variable names to produce consecutive character blocks, except for variables

RegPack v3.0.1 Score = *gain + *length + *copies     Tiebreaker =
Default settings match built-in formulas for both JS Crush and First Crush. 2/1/0 sometimes achieve better results.

Preprocessed :

Crushed :

RegPack'ed: