Which Javascript minifier (cruncher) does the same things that the one Google uses for its JS APIs?

Question

I am a Google Maps API (javascript) developer. I have noticed that Google uses a Javascript minifier that has the following features:

1. Shortens variables, prope

Answer 1

I believe that YUICompressor does #1, except for the function names, and #2 using a special syntax that is removed during compression.

#3 is just a build task, not a function of the compressor.

YUICompressor