Day 19/420: Datetime, time zones, and timestamps
Today's note was about turning datetime, time zones, and timestamps into something I can explain from the code instead of memorizing from a tutorial. I kept coming back to the same checks: data shapes that stay obvious at a glance, control flow that makes valid states visible, and small units of logic that remain easy to test.
The failure mode worth watching is letting convenience hide where state changes actually happen.…
