🔧 I got tired of mocking Date, so I built a TimeProvider for TypeScript

Every (or at least a lot of) project seems to have code like this somewhere:

if (user.subscriptionEndsAt < new Date()) {
// ...
}

There's nothing wrong with it... until you have to test it.

Then you end up freezing time, mocking Date, enabling fake timers, remembering to restore them afterwards, and hoping another test didn't leave the...