The default compilation level is WHITESPACE_ONLY. Another level can be
specified with the
--level option. SIMPLE_OPTIMIZATIONS can be
abbreviated as simple, ADVANCED_OPTIMIZATIONS as advanced, and
WHITESPACE_ONLY as whitespace.
js-compile some.js performs whitespace-only compression on the
file named some.js.
js-compile --level=advanced <some.js >compressed.js
performs advanced compression on the files it receives via STDIN, then writes
then concatenated result to compressed.js.