// Ignore all milliseconds before a certain time to reduce the size of the date entropy without sacrificing uniqueness.
// This number should be updated every year or so to keep the generated id short.
// To regenerate `new Date() - 0` and bump the version. Always bump the version!
var REDUCE_TIME = 1459707606518;
I was looking at the source code and found this:
https://github.com/dylang/shortid/blob/318ff16938f92203538c6dc5b1a6cc2b4bd3d0fa/lib/build.js#L6