datetime/iso_interval_parse_utils library

ISO 8601 time-interval parser — roadmap #646.

Parses the three interval forms from ISO 8601 into a DateTimeRange:

  • start/end — two timestamps (2026-01-01T00:00Z/2026-01-02T00:00Z)
  • start/duration — a timestamp plus a duration (2026-01-01/P1M)
  • duration/end — a duration ending at a timestamp (P7D/2026-01-08)

The timestamp halves use Dart's native ISO 8601 datetime parsing; the duration half is an ISO 8601 duration (P[nY][nM][nW][nD][T[nH][nM][nS]]) applied with calendar arithmetic (years/months add as calendar units, not a fixed number of days). Anything malformed throws a FormatException.

Functions

parseIsoInterval(String input) → DateTimeRange<DateTime>
Parses an ISO 8601 time interval into a DateTimeRange. Accepts the start/end, start/duration, and duration/end forms, separated by /. Throws a FormatException if the separator is missing, either half is malformed, both halves are durations, or start ends up after end.