Author of JShrink here (I found you guys in my web logs). I thought I'd pop in and say hello, and talk about JShrink a bit.
I originally made it as a drop in replacement for JSMin, because JSMin is technically not open source (it has the "do no evil" license, so projects that take open source seriously, such as Debian, won't bundle projects with it). Since then I've made improvements on speed, added additional features like support for conditional comments and license preservation, and have really put work into the test suite itself. Ryan Grove, who originally ported JSMin to PHP, has officially dropped the JSMin project and is referring people to JShrink on the Github page for it.
Yesterday, after several years of being in the "beta" phase, I launched the JShrink v1.0 to make the API official and stable.
On a tangental note, I also maintain a caching library called Stash that may be useful to you.