RRule

Description

RRule is a minimalist package for expanding RRULEs, with a goal of being fully compliant with iCalendar spec.

Examples

To use this package, add this to your code:

import RRule

Create a rrule with a RRULE string:

let rrule = RRule.parse('FREQ=DAILY;COUNT=3')

Generating recurrence instances

Either generate all instances of a recurrence, or generate instances in a range:

rrule.all
// [2024-06-23 16:45:32 -0700, 2024-06-24 16:45:32 -0700, 2024-06-25 16:45:32 -0700]

let startDate = Calendar.current.date(from: DateComponents(year: 2024, month: 6, day: 23))
let endDate = Calendar.current.date(from: DateComponents(year: 2024, month: 6, day: 24))
rrule.between(startDate: startDate, endDate: endDate)
// [2024-06-23 16:45:32 -0700]

You can generate all instances starting from a specified date with the #from method:

let startDate = Calendar.current.date(from: DateComponents(year: 2024, month: 1, day: 1))
let rrule = RRule.parse('FREQ=DAILY;COUNT=3', startDate)
rrule.all
// [2024-01-01 16:45:32 -0700, 2024-01-02 16:45:32 -0700, 2024-01-03 16:45:32 -0700]

let date = Calendar.current.date(from: DateComponents(year: 2024, month: 1, day: 2))
rrule.from(startDate: date)
// [2024-01-02 16:45:32 -0700, 2024-01-03 16:45:32 -0700]

You can limit the number of instances that are returned with the limit option:

let rrule = RRule.parse('FREQ=DAILY;COUNT=3')
rrule.all(limit: 2)
=> [2016-06-23 16:45:32 -0700, 2016-06-24 16:45:32 -0700]

By default the DTSTART of the recurrence is the current time, but this can be overriden with the dtstart option:

let date = Calendar.current.date(from: DateComponents(year: 2024, month: 7, day: 2))
let rrule = RRule.parse('FREQ=DAILY;COUNT=3', dtstart: date)
rrule.all
=> [2024-07-01 00:00:00 -0700, 2024-07-02 00:00:00 -0700, 2024-07-03 00:00:00 -0700]

Unless your rrule should be evaluated in UTC time, you should also pass an explicit timezone in the tzid option to ensure that daylight saving time boundaries are respected, etc.:

let date = Calendar.current.date(from: DateComponents(year: 2024, month: 7, day: 1))
let rrule = RRule.parse('FREQ=DAILY;COUNT=3', dtstart: date, tzid: 'America/Los_Angeles')

Exceptions (EXDATEs)

To define exception dates, pass the exdate option:

let startDate = Calendar.current.date(from: DateComponents(year: 2024, month: 7, day: 1))
let exDate = Calendar.current.date(from: DateComponents(year: 2024, month: 7, day: 2))
let rrule = RRule.parse('FREQ=DAILY;COUNT=3', dtstart: startDate, exdate: [exDate])
rrule.all
=> [2024-07-01 00:00:00 -0700, 2024-07-03 00:00:00 -0700]

Contributing

Contributions are welcome! Report bugs and submit pull requests on GitHub.

License

This package is open source under the MIT License.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.