hron (Dart)

Native Dart implementation of hron — human-readable cron expressions for Flutter and Dart.

Install

dart pub add hron

Usage

import 'package:hron/hron.dart';
import 'package:timezone/data/latest.dart' as tz;

void main() {
  // Required: initialize timezone database
  tz.initializeTimeZones();

  // Parse an expression
  final schedule = Schedule.parse('every weekday at 9:00 in America/New_York');

  // Compute next occurrence
  final now = TZDateTime.now(getLocation('America/New_York'));
  final next = schedule.nextFrom(now);

  // Compute next N occurrences
  final nextFive = schedule.nextNFrom(now, 5);

  // Check if a datetime matches
  final matches = schedule.matches(now);

  // Convert to cron (expressible subset only)
  final cron = Schedule.parse('every day at 9:00').toCron();

  // Convert from cron
  final fromCron = Schedule.fromCron('0 9 * * *');

  // Canonical string (roundtrip-safe)
  print(schedule.toString());
}

Timezone Support

This package depends on the timezone package for IANA timezone support. You must call initializeTimeZones() before using hron:

import 'package:timezone/data/latest.dart' as tz;
tz.initializeTimeZones();

Tests

dart test

Conformance tests driven by spec/tests.json.

License

MIT