RegPack, now in its third version, is a packer intended for use on minified Javascript code.
It is mostly suited to small size constraints (1kb, up to 4kb).

The current version works in five stages :
 - (if enabled) 2D, WebGL and Audio contexts method shortcuts are defined and used instead of the long, original names.
 - (if enabled) variables are renamed in order to reduce character footprint and free tokens for compression.
 - redundancies are eliminated and replaced by tokens, as done by JS Crush (by Aivo Paas) and First Crush (by Tim Down).
 - the token list is turned into a regular expression consisting in a character class. 
 - the tokens are rearranged to create a negated character class (starting with a hyphen ^ then listing nontoken characters)
 
The text boxes show intermediate stage results. Best one gets a green highlight :
 - Preprocessed : after the first two stages. Hidden if no change was brought to the initial code.
 - Crushed : after the third stage
 - RegPack'ed : best between fourth and fifth stage. Depends on how the characters present in the string are spread in the ASCII table.

Tips for using RegPack :
  - Toggle method hashing for any type of context you use. If the method renaming yields a longer code, RegPack will revert to the original one.
  - "Assume global .. is a context" is for environments where the canvas is declared before your code. If entering js1k, keep this on, variable is c for classic and ++, and g for webgl.
  - Variable renaming is also performed inside strings, RegPack does not infer whether they are eval()ed or not. Disable if facing issues with this. Only one-letter variables are considered, others are ignored.
  - Crusher settings alter the choice of strings to compress. 1/0/0 is a good allrounder, although more exotic values can yield better results depending on your code.
  - "Pack with(Math)" get rid of all "Math." references in the code and enclose the evaluation with(Math). May gain a few extra bytes, but likely to slow down the execution.
  
Use it online at : http://siorki.github.io/regPack.html
  
Any feedback or improvement suggestions appreciated.
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