Sam shares some recent learnings around hydration mismatches when rendering time zoned dates on the server and the client. He talks about using the TZ environment variable to reproduce the issue locally, and how he solved his problem by avoiding impure format and transformation functions from date-fns.

Topics include:

• 0:00 - Intro
• 0:50 - Sever vs. client time zone mismatches, and the TZ environment variable
• 14:34 - Which date-fns functions are impure?
• 23:56 - Using intervals and comparison to remove impurities

Links:

• date-fns
• date-fns-tz