built-in-temporal-types
Built-In Temporal Types
Goal
Represent temporal values with built-in or standard-library temporal types that match their real meaning.
Use date-like types for calendar dates, time-like types for wall-clock times, and datetime-like types for date-and-time values. Do not represent temporal values as generic strings, numbers, or loose objects when the language or standard library already provides an appropriate temporal type.
When timezone semantics matter, use a representation that preserves a geographic timezone, such as an IANA timezone like America/Mexico_City or Europe/Berlin. A fixed offset such as -06:00 or +01:00 is not a geographic timezone and is not enough to model daylight saving time transitions.
What Counts as In Scope
Apply this skill to code that does one or more of these things:
- defines date, time, datetime, timestamp, schedule, deadline, or recurrence fields
- defines temporal parameters or return types
- parses or serializes temporal values
- maps temporal values to persistence or transport boundaries
- calculates or compares temporal values
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