Comparing dates in Elixir

Elixir 1.15 introduced new DateTime and Date functions to compare dates.

Let’s cover the new functions, what already exists, and what to avoid at all costs!

• DateTime.before?/2, DateTime.after?/2 (and their Date counterparts) are new (since Elixir 1.15) and allow for strict comparison of datetimes (and dates),
• We’ve had DateTime.compare/2 for a while, and it returns :gt, :lt, or :eq. The nice thing about compare/2 is that it has equality.
• Never use <, >, == to compare dates or datetimes! They perform structural comparisons. They don’t understand semantics. For more, take a look at the docs on structural comparison.