This is a pretty naive minifier for vanilla Javascript.
What I mean by naive, is that it assumes your Javascript input has already been validated, and that it (currently) doesn't even do a lot of the fancier tricks minifiers do these days. That being said, it's a single, small file, runs very quickly (see below), and you should still expect a file size reduction between 20 and 40 percent.
Minifying a fairly small file with almost no comments still gets you decent savings:
> ./miniminify js.js
Minified file: js.js
initial size (kb): 68.479, minified: 50.829, a 25.77% reduction.
| raw time (milliseconds) | time/kb
| fread time: 0.1010 | 0.0015
| minify time: 0.3210 | 0.0047
| fwrite time: 0.3350 | 0.0049
| total time: 0.7570 | 0.0111
More test cases for robustness, better speed, and better size reduction to come.
Run make.