buildTimeFromId function
Extracts the UTC build time embedded in a build ID made by
formatBuildId, or null when buildId has another format.
Implementation
DateTime? buildTimeFromId(String buildId) {
final RegExpMatch? m = _buildIdPattern.firstMatch(buildId);
if (m == null) return null;
final String s = m.group(2)!;
return DateTime.utc(
int.parse(s.substring(0, 4)),
int.parse(s.substring(4, 6)),
int.parse(s.substring(6, 8)),
int.parse(s.substring(9, 11)),
int.parse(s.substring(11, 13)),
int.parse(s.substring(13, 15)),
);
}