tryParse static method

IsoDuration? tryParse(String input)

Like parse but safely parses the ISO 8601 - Duration and returns null if the input is invalid.

Implementation

static IsoDuration? tryParse(String input) {
  final regExp = RegExp(_pattern);
  final matches = regExp.matchAsPrefix(input);

  if (matches != null) {
    final y = matches.group(2)?.replaceFirst('Y', '').replaceComma();
    final m = matches.group(3)?.replaceFirst('M', '').replaceComma();
    final w = matches.group(4)?.replaceFirst('W', '').replaceComma();

    final d = matches.group(5)?.replaceFirst('D', '').replaceComma();
    final hrs = matches.group(7)?.replaceFirst('H', '').replaceComma();
    final min = matches.group(8)?.replaceFirst('M', '').replaceComma();
    final sec = matches.group(9)?.replaceFirst('S', '').replaceComma();

    // additional check if some input was wrongly matched
    if (<String?>[y, m, w, d, hrs, min, sec].any(
      (element) {
        if (element == null) return false;
        if (double.tryParse(element) == null) return true;
        return false;
      },
    )) {
      return null;
    }

    final years = double.tryParse(y ?? '');
    final months = double.tryParse(m ?? '');
    final weeks = double.tryParse(w ?? '');
    final days = double.tryParse(d ?? '');
    final hours = double.tryParse(hrs ?? '');
    final minutes = double.tryParse(min ?? '');
    final seconds = double.tryParse(sec ?? '');

    final isNegative = matches.group(1) == '-';
    final multipl = isNegative ? -1 : 1;

    return IsoDuration(
      years: (years ?? 0) * multipl,
      months: (months ?? 0) * multipl,
      weeks: (weeks ?? 0) * multipl,
      days: (days ?? 0) * multipl,
      hours: (hours ?? 0) * multipl,
      minutes: (minutes ?? 0) * multipl,
      seconds: (seconds ?? 0) * multipl,
    );
  }
  return null;
}