Cyclical.js

Recurring events library for JavaScript calendar applications.

About

Cyclical lets you list recurring events with complex recurrence rules like "every 4 years, the first Tuesday after a Monday in November" in a simple way. The API is inspired by ice_cube and uses method chaining for natural rule specification.

You can find out if a given time matches the schedule, list event occurrences or add event duration and list suboccurrences in a given interval, which is handy when you need to trim event occurences to the interval (like rendering a day in a week view of a calendar with events crossing midnight).

Cyclical was originally extracted from a browser based calendar application and is written in Coffeescript. The plan is to translate it to plain JavaScript in the future.

Missing features and TODO

• Rule exception dates
• Hourly and secondly rules
• Switch from datejs to moment.js
• Remove the underscore.js dependency
• Translate to plain JavaScript

Install

You can install Cyclical using npm

npm install cyclical

or download dist/cyclical.x.js or dist/cyclical.x.min.js file.

Dependencies

Cyclical currently depends on date.js and underscore.js. See package.json for specific versions.

Usage

The central thing in Cyclical is the Schedule. Let's take the example of U.S. Presidential Election day from RFC 5545:

  date = new Date(1997, 8, 2, 9, 0, 0);
  schedule = new Schedule(date, Schedule.Rule.yearly(4).month(11).weekday('tue').monthdays(2, 3, 4, 5, 6, 7, 8));

  election_dates = schedule.first(3);

Creating schedules

Each schedule has a base date and a recurrence rule. The four supported rules are:

• daily
• weekly
• monthly
• yearly

with corresponding factory methods on Schedule.Rule. The factory methods take a single argument - the repetition interval.

The basic recurrence rule matches the original date, i.e. for a yearly rule, the occurences will always happen on the same date. To specify a more complex pattern, you can use filters.

Filters replace the single value (day, month) with a set of values that match. For example, instead of only matching the day of month in of the base date, with the monthdays filter, you can match multiple month days.

Available filters are:

• weekday(s)
• monthday(s)
• yearday(s)
• month(s)

Each filter methord takes variable arguments containing integers or string (incl. shortcuts) for a given date component.

You can limit the schedule either by a number of events (using the count method) or an end date (using the stop method).

Querying occurrences and suboccurrences

TODO. See lib/schedule.js.coffee

Serialization

TODO. See lib/schedule.js.coffee

More examples

TODO

License

Cyclical is released under the MIT License.