Lawrence  Lesch

Lawrence Lesch

1673020680

RRule: Library for Working with Recurrence Rules For Calendar Dates

rrule.js

Library for working with recurrence rules for calendar dates.

rrule.js supports recurrence rules as defined in the iCalendar RFC, with a few important differences. It is a partial port of the rrule module from the excellent python-dateutil library. On top of that, it supports parsing and serialization of recurrence rules from and to natural language.


Quick Start

For contributors and maintainers: the code for the demo app is only on gh-pages branch

Client Side

$ yarn add rrule

Alternatively, download manually:

<script src="rrule/dist/es5/rrule.min.js"></script>

Server Side

Includes optional TypeScript types

$ yarn add rrule
# or
$ npm install rrule

Usage

RRule:

import { datetime, RRule, RRuleSet, rrulestr } from 'rrule'

// Create a rule:
const rule = new RRule({
  freq: RRule.WEEKLY,
  interval: 5,
  byweekday: [RRule.MO, RRule.FR],
  dtstart: datetime(2012, 2, 1, 10, 30),
  until: datetime(2012, 12, 31)
})

// Get all occurrence dates (Date instances):
rule.all()
[ '2012-02-03T10:30:00.000Z',
  '2012-03-05T10:30:00.000Z',
  '2012-03-09T10:30:00.000Z',
  '2012-04-09T10:30:00.000Z',
  '2012-04-13T10:30:00.000Z',
  '2012-05-14T10:30:00.000Z',
  '2012-05-18T10:30:00.000Z',

 /* … */]

// Get a slice:
rule.between(datetime(2012, 8, 1), datetime(2012, 9, 1))
['2012-08-27T10:30:00.000Z',
 '2012-08-31T10:30:00.000Z']

// Get an iCalendar RRULE string representation:
// The output can be used with RRule.fromString().
rule.toString()
"DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;INTERVAL=5;UNTIL=20130130T230000Z;BYDAY=MO,FR"

// Get a human-friendly text representation:
// The output can be used with RRule.fromText().
rule.toText()
"every 5 weeks on Monday, Friday until January 31, 2013"

RRuleSet:

const rruleSet = new RRuleSet()

// Add a rrule to rruleSet
rruleSet.rrule(
  new RRule({
    freq: RRule.MONTHLY,
    count: 5,
    dtstart: datetime(2012, 2, 1, 10, 30),
  })
)

// Add a date to rruleSet
rruleSet.rdate(datetime(2012, 7, 1, 10, 30))

// Add another date to rruleSet
rruleSet.rdate(datetime(2012, 7, 2, 10, 30))

// Add a exclusion rrule to rruleSet
rruleSet.exrule(
  new RRule({
    freq: RRule.MONTHLY,
    count: 2,
    dtstart: datetime(2012, 3, 1, 10, 30),
  })
)

// Add a exclusion date to rruleSet
rruleSet.exdate(datetime(2012, 5, 1, 10, 30))

// Get all occurrence dates (Date instances):
rruleSet.all()[
  ('2012-02-01T10:30:00.000Z',
  '2012-05-01T10:30:00.000Z',
  '2012-07-01T10:30:00.000Z',
  '2012-07-02T10:30:00.000Z')
]

// Get a slice:
rruleSet.between(datetime(2012, 2, 1), datetime(2012, 6, 2))[
  ('2012-05-01T10:30:00.000Z', '2012-07-01T10:30:00.000Z')
]

// To string
rruleSet.valueOf()[
  ('DTSTART:20120201T023000Z',
  'RRULE:FREQ=MONTHLY;COUNT=5',
  'RDATE:20120701T023000Z,20120702T023000Z',
  'EXRULE:FREQ=MONTHLY;COUNT=2',
  'EXDATE:20120601T023000Z')
]

// To string
rruleSet.toString()
;('["DTSTART:20120201T023000Z","RRULE:FREQ=MONTHLY;COUNT=5","RDATE:20120701T023000Z,20120702T023000Z","EXRULE:FREQ=MONTHLY;COUNT=2","EXDATE:20120601T023000Z"]')

rrulestr:

// Parse a RRule string, return a RRule object
rrulestr('DTSTART:20120201T023000Z\nRRULE:FREQ=MONTHLY;COUNT=5')

// Parse a RRule string, return a RRuleSet object
rrulestr('DTSTART:20120201T023000Z\nRRULE:FREQ=MONTHLY;COUNT=5', {
  forceset: true,
})

// Parse a RRuleSet string, return a RRuleSet object
rrulestr(
  'DTSTART:20120201T023000Z\nRRULE:FREQ=MONTHLY;COUNT=5\nRDATE:20120701T023000Z,20120702T023000Z\nEXRULE:FREQ=MONTHLY;COUNT=2\nEXDATE:20120601T023000Z'
)

Important: Use UTC dates

Dates in JavaScript are tricky. RRule tries to support as much flexibility as possible without adding any large required 3rd party dependencies, but that means we also have some special rules.

By default, RRule deals in "floating" times or UTC timezones. If you want results in a specific timezone, RRule also provides timezone support. Either way, JavaScript's built-in "timezone" offset tends to just get in the way, so this library simply doesn't use it at all. All times are returned with zero offset, as though it didn't exist in JavaScript.

The bottom line is the returned "UTC" dates are always meant to be interpreted as dates in your local timezone. This may mean you have to do additional conversion to get the "correct" local time with offset applied.

For this reason, it is highly recommended to use timestamps in UTC eg. new Date(Date.UTC(...)). Returned dates will likewise be in UTC (except on Chrome, which always returns dates with a timezone offset). It's recommended to use the provided datetime helper, which creates dates in the correct format using a 1-based month.

For example:

// local machine zone is America/Los_Angeles
const rule = RRule.fromString(
  "DTSTART;TZID=America/Denver:20181101T190000;\n"
  + "RRULE:FREQ=WEEKLY;BYDAY=MO,WE,TH;INTERVAL=1;COUNT=3"
)
rule.all()

[ 2018-11-01T18:00:00.000Z,
  2018-11-05T18:00:00.000Z,
  2018-11-07T18:00:00.000Z ]
// Even though the given offset is `Z` (UTC), these are local times, not UTC times.
// Each of these this is the correct local Pacific time of each recurrence in
// America/Los_Angeles when it is 19:00 in America/Denver, including the DST shift.

// You can get the local components by using the getUTC* methods eg:
date.getUTCDate() // --> 1
date.getUTCHours() // --> 18

If you want to get the same times in true UTC, you may do so eg. using Luxon:

rule.all().map(date =>
DateTime.fromJSDate(date)
  .toUTC()
  .setZone('local', { keepLocalTime: true })
  .toJSDate()
)

[ 2018-11-02T01:00:00.000Z,
  2018-11-06T02:00:00.000Z,
  2018-11-08T02:00:00.000Z ]
// These times are in true UTC; you can see the hours shift

For more examples see python-dateutil documentation.


Timezone Support

Rrule also supports use of the TZID parameter in the RFC using the Intl API. Support matrix for the Intl API applies. If you need to support additional environments, please consider using a polyfill.

Example with TZID:

new RRule({
  dtstart: datetime(2018, 2, 1, 10, 30),
  count: 1,
  tzid: 'Asia/Tokyo',
}).all()[
  // assuming the system timezone is set to America/Los_Angeles, you get:
  '2018-01-31T17:30:00.000Z'
]
// which is the time in Los Angeles when it's 2018-02-01T10:30:00 in Tokyo.

Whether or not you use the TZID param, make sure to only use JS Date objects that are represented in UTC to avoid unexpected timezone offsets being applied, for example:

// WRONG: Will produce dates with TZ offsets added
new RRule({
  freq: RRule.MONTHLY,
  dtstart: new Date(2018, 1, 1, 10, 30),
  until: new Date(2018, 2, 31),
}).all()[('2018-02-01T18:30:00.000Z', '2018-03-01T18:30:00.000Z')]

// RIGHT: Will produce dates with recurrences at the correct time
new RRule({
  freq: RRule.MONTHLY,
  dtstart: datetime(2018, 2, 1, 10, 30),
  until: datetime(2018, 3, 31),
}).all()[('2018-02-01T10:30:00.000Z', '2018-03-01T10:30:00.000Z')]

API

RRule Constructor

new RRule(options[, noCache=false])

The options argument mostly corresponds to the properties defined for RRULE in the iCalendar RFC. Only freq is required.

OptionDescription
freq

(required) One of the following constants:

  • RRule.YEARLY
  • RRule.MONTHLY
  • RRule.WEEKLY
  • RRule.DAILY
  • RRule.HOURLY
  • RRule.MINUTELY
  • RRule.SECONDLY
dtstartThe recurrence start. Besides being the base for the recurrence, missing parameters in the final recurrence instances will also be extracted from this date. If not given, new Date will be used instead. **IMPORTANT:** See the discussion under timezone support
intervalThe interval between each freq iteration. For example, when using RRule.YEARLY, an interval of 2 means once every two years, but with RRule.HOURLY, it means once every two hours. The default interval is 1.
wkstThe week start day. Must be one of the RRule.MO, RRule.TU, RRule.WE constants, or an integer, specifying the first day of the week. This will affect recurrences based on weekly periods. The default week start is RRule.MO.
countHow many occurrences will be generated.
untilIf given, this must be a Date instance, that will specify the limit of the recurrence. If a recurrence instance happens to be the same as the Date instance given in the until argument, this will be the last occurrence.
tzidIf given, this must be a IANA string recognized by the Intl API. See discussion under Timezone support.
bysetposIf given, it must be either an integer, or an array of integers, positive or negative. Each given integer will specify an occurrence number, corresponding to the nth occurrence of the rule inside the frequency period. For example, a bysetpos of -1 if combined with a RRule.MONTHLY frequency, and a byweekday of (RRule.MO, RRule.TU, RRule.WE, RRule.TH, RRule.FR), will result in the last work day of every month.
bymonthIf given, it must be either an integer, or an array of integers, meaning the months to apply the recurrence to.
bymonthdayIf given, it must be either an integer, or an array of integers, meaning the month days to apply the recurrence to.
byyeardayIf given, it must be either an integer, or an array of integers, meaning the year days to apply the recurrence to.
byweeknoIf given, it must be either an integer, or an array of integers, meaning the week numbers to apply the recurrence to. Week numbers have the meaning described in ISO8601, that is, the first week of the year is that containing at least four days of the new year.
byweekdayIf given, it must be either an integer (0 == RRule.MO), an array of integers, one of the weekday constants (RRule.MO, RRule.TU, etc), or an array of these constants. When given, these variables will define the weekdays where the recurrence will be applied. It's also possible to use an argument n for the weekday instances, which will mean the nth occurrence of this weekday in the period. For example, with RRule.MONTHLY, or with RRule.YEARLY and BYMONTH, using RRule.FR.nth(+1) or RRule.FR.nth(-1) in byweekday will specify the first or last friday of the month where the recurrence happens. Notice that the RFC documentation, this is specified as BYDAY, but was renamed to avoid the ambiguity of that argument.
byhourIf given, it must be either an integer, or an array of integers, meaning the hours to apply the recurrence to.
byminuteIf given, it must be either an integer, or an array of integers, meaning the minutes to apply the recurrence to.
bysecondIf given, it must be either an integer, or an array of integers, meaning the seconds to apply the recurrence to.
byeasterThis is an extension to the RFC specification which the Python implementation provides. Not implemented in the JavaScript version.

noCache: Set to true to disable caching of results. If you will use the same rrule instance multiple times, enabling caching will improve the performance considerably. Enabled by default.

See also python-dateutil documentation.


Instance properties

rule.options

Processed options applied to the rule. Includes default options (such us wkstart). Currently, rule.options.byweekday isn't equal to rule.origOptions.byweekday (which is an inconsistency).

rule.origOptions

The original options argument passed to the constructor.


Occurrence Retrieval Methods

RRule.prototype.all([iterator])

Returns all dates matching the rule. It is a replacement for the iterator protocol this class implements in the Python version.

As rules without until or count represent infinite date series, you can optionally pass iterator, which is a function that is called for each date matched by the rule. It gets two parameters date (the Date instance being added), and i (zero-indexed position of date in the result). Dates are being added to the result as long as the iterator returns true. If a false-y value is returned, date isn't added to the result and the iteration is interrupted (possibly prematurely).

rule.all()[
  ('2012-02-01T10:30:00.000Z',
  '2012-05-01T10:30:00.000Z',
  '2012-07-01T10:30:00.000Z',
  '2012-07-02T10:30:00.000Z')
]

rule.all(function (date, i) {
  return i < 2
})[('2012-02-01T10:30:00.000Z', '2012-05-01T10:30:00.000Z')]

RRule.prototype.between(after, before, inc=false [, iterator])

Returns all the occurrences of the rrule between after and before. The inc keyword defines what happens if after and/or before are themselves occurrences. With inc == true, they will be included in the list, if they are found in the recurrence set.

Optional iterator has the same function as it has with RRule.prototype.all().

rule.between(datetime(2012, 8, 1), datetime(2012, 9, 1))[
  ('2012-08-27T10:30:00.000Z', '2012-08-31T10:30:00.000Z')
]

RRule.prototype.before(dt, inc=false)

Returns the last recurrence before the given Date instance. The inc argument defines what happens if dt is an occurrence. With inc == true, if dt itself is an occurrence, it will be returned.

RRule.prototype.after(dt, inc=false)

Returns the first recurrence after the given Date instance. The inc argument defines what happens if dt is an occurrence. With inc == true, if dt itself is an occurrence, it will be returned.

See also python-dateutil documentation.


iCalendar RFC String Methods

RRule.prototype.toString()

Returns a string representation of the rule as per the iCalendar RFC. Only properties explicitly specified in options are included:

rule.toString()
;('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;INTERVAL=5;UNTIL=20130130T230000Z;BYDAY=MO,FR')

rule.toString() == RRule.optionsToString(rule.origOptions)
true

RRule.optionsToString(options)

Converts options to iCalendar RFC RRULE string:

// Get full a string representation of all options,
// including the default and inferred ones.
RRule.optionsToString(rule.options)
;('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;INTERVAL=5;WKST=0;UNTIL=20130130T230000Z;BYDAY=MO,FR;BYHOUR=10;BYMINUTE=30;BYSECOND=0')

// Cherry-pick only some options from an rrule:
RRule.optionsToString({
  freq: rule.options.freq,
  dtstart: rule.options.dtstart,
})
;('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;')

RRule.fromString(rfcString)

Constructs an RRule instance from a complete rfcString:

var rule = RRule.fromString('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;')

// This is equivalent
var rule = new RRule(
  RRule.parseString('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY')
)

RRule.parseString(rfcString)

Only parse RFC string and return options.

var options = RRule.parseString('FREQ=DAILY;INTERVAL=6')
options.dtstart = datetime(2000, 2, 1)
var rule = new RRule(options)

Natural Language Text Methods

These methods provide an incomplete support for text–RRule and RRule–text conversion. You should test them with your input to see whether the result is acceptable.

RRule.prototype.toText([gettext, [language]])

Returns a textual representation of rule. The gettext callback, if provided, will be called for each text token and its return value used instead. The optional language argument is a language definition to be used (defaults to rrule/nlp.js:ENGLISH).

var rule = new RRule({
  freq: RRule.WEEKLY,
  count: 23,
})
rule.toText()
;('every week for 23 times')

RRule.prototype.isFullyConvertibleToText()

Provides a hint on whether all the options the rule has are convertible to text.

RRule.fromText(text[, language])

Constructs an RRule instance from text.

rule = RRule.fromText('every day for 3 times')

RRule.parseText(text[, language])

Parse text into options:

options = RRule.parseText('every day for 3 times')
// {freq: 3, count: "3"}
options.dtstart = datetime(2000, 2, 1)
var rule = new RRule(options)

RRuleSet Constructor

new RRuleSet([(noCache = false)])

The RRuleSet instance allows more complex recurrence setups, mixing multiple rules, dates, exclusion rules, and exclusion dates.

Default noCache argument is false, caching of results will be enabled, improving performance of multiple queries considerably.

RRuleSet.prototype.rrule(rrule)

Include the given rrule instance in the recurrence set generation.

RRuleSet.prototype.rdate(dt)

Include the given datetime instance in the recurrence set generation.

RRuleSet.prototype.exrule(rrule)

Include the given rrule instance in the recurrence set exclusion list. Dates which are part of the given recurrence rules will not be generated, even if some inclusive rrule or rdate matches them. NOTE: EXRULE has been (deprecated in RFC 5545)[https://icalendar.org/iCalendar-RFC-5545/a-3-deprecated-features.html] and does not support a DTSTART property.

RRuleSet.prototype.exdate(dt)

Include the given datetime instance in the recurrence set exclusion list. Dates included that way will not be generated, even if some inclusive rrule or rdate matches them.

RRuleSet.prototype.tzid(tz?)

Sets or overrides the timezone identifier. Useful if there are no rrules in this RRuleSet and thus no DTSTART.

RRuleSet.prototype.all([iterator])

Same as RRule.prototype.all.

RRuleSet.prototype.between(after, before, inc=false [, iterator])

Same as RRule.prototype.between.

RRuleSet.prototype.before(dt, inc=false)

Same as RRule.prototype.before.

RRuleSet.prototype.after(dt, inc=false)

Same as RRule.prototype.after.

RRuleSet.prototype.rrules()

Get list of included rrules in this recurrence set.

RRuleSet.prototype.exrules()

Get list of excluded rrules in this recurrence set.

RRuleSet.prototype.rdates()

Get list of included datetimes in this recurrence set.

RRuleSet.prototype.exdates()

Get list of excluded datetimes in this recurrence set.


rrulestr Function

rrulestr(rruleStr[, options])

The rrulestr function is a parser for RFC-like syntaxes. The string passed as parameter may be a multiple line string, a single line string, or just the RRULE property value.

Additionally, it accepts the following keyword arguments:

cache If True, the rruleset or rrule created instance will cache its results. Default is not to cache.

dtstart If given, it must be a datetime instance that will be used when no DTSTART property is found in the parsed string. If it is not given, and the property is not found, datetime.now() will be used instead.

unfold If set to True, lines will be unfolded following the RFC specification. It defaults to False, meaning that spaces before every line will be stripped.

forceset If set to True a rruleset instance will be returned, even if only a single rule is found. The default is to return an rrule if possible, and an rruleset if necessary.

compatible If set to True, the parser will operate in RFC-compatible mode. Right now it means that unfold will be turned on, and if a DTSTART is found, it will be considered the first recurrence instance, as documented in the RFC.

tzid If given, it must be a string that will be used when no TZID property is found in the parsed string. If it is not given, and the property is not found, 'UTC' will be used by default.


Differences From iCalendar RFC

  • RRule has no byday keyword. The equivalent keyword has been replaced by the byweekday keyword, to remove the ambiguity present in the original keyword.
  • Unlike documented in the RFC, the starting datetime, dtstart, is not the first recurrence instance, unless it does fit in the specified rules. This is in part due to this project being a port of python-dateutil, which has the same non-compliant functionality. Note that you can get the original behavior by using a RRuleSet and adding the dtstart as an rdate.
var rruleSet = new RRuleSet()
var start = datetime(2012, 2, 1, 10, 30)

// Add a rrule to rruleSet
rruleSet.rrule(
  new RRule({
    freq: RRule.MONTHLY,
    count: 5,
    dtstart: start,
  })
)

// Add a date to rruleSet
rruleSet.rdate(start)
  • Unlike documented in the RFC, every keyword is valid on every frequency (the RFC documents that byweekno is only valid on yearly frequencies, for example).

Development

rrule.js is implemented in Typescript. It uses JavaScript Standard Style coding style.

To run the code, checkout this repository and run:

$ yarn

To run the tests, run:

$ yarn test

To build files for distribution, run:

$ yarn build

Download Details:

Author: jakubroztocil
Source Code: https://github.com/jakubroztocil/rrule 
License: View license

#typescript #javascript #library #calendar 

What is GEEK

Buddha Community

RRule: Library for Working with Recurrence Rules For Calendar Dates
Lawrence  Lesch

Lawrence Lesch

1673020680

RRule: Library for Working with Recurrence Rules For Calendar Dates

rrule.js

Library for working with recurrence rules for calendar dates.

rrule.js supports recurrence rules as defined in the iCalendar RFC, with a few important differences. It is a partial port of the rrule module from the excellent python-dateutil library. On top of that, it supports parsing and serialization of recurrence rules from and to natural language.


Quick Start

For contributors and maintainers: the code for the demo app is only on gh-pages branch

Client Side

$ yarn add rrule

Alternatively, download manually:

<script src="rrule/dist/es5/rrule.min.js"></script>

Server Side

Includes optional TypeScript types

$ yarn add rrule
# or
$ npm install rrule

Usage

RRule:

import { datetime, RRule, RRuleSet, rrulestr } from 'rrule'

// Create a rule:
const rule = new RRule({
  freq: RRule.WEEKLY,
  interval: 5,
  byweekday: [RRule.MO, RRule.FR],
  dtstart: datetime(2012, 2, 1, 10, 30),
  until: datetime(2012, 12, 31)
})

// Get all occurrence dates (Date instances):
rule.all()
[ '2012-02-03T10:30:00.000Z',
  '2012-03-05T10:30:00.000Z',
  '2012-03-09T10:30:00.000Z',
  '2012-04-09T10:30:00.000Z',
  '2012-04-13T10:30:00.000Z',
  '2012-05-14T10:30:00.000Z',
  '2012-05-18T10:30:00.000Z',

 /* … */]

// Get a slice:
rule.between(datetime(2012, 8, 1), datetime(2012, 9, 1))
['2012-08-27T10:30:00.000Z',
 '2012-08-31T10:30:00.000Z']

// Get an iCalendar RRULE string representation:
// The output can be used with RRule.fromString().
rule.toString()
"DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;INTERVAL=5;UNTIL=20130130T230000Z;BYDAY=MO,FR"

// Get a human-friendly text representation:
// The output can be used with RRule.fromText().
rule.toText()
"every 5 weeks on Monday, Friday until January 31, 2013"

RRuleSet:

const rruleSet = new RRuleSet()

// Add a rrule to rruleSet
rruleSet.rrule(
  new RRule({
    freq: RRule.MONTHLY,
    count: 5,
    dtstart: datetime(2012, 2, 1, 10, 30),
  })
)

// Add a date to rruleSet
rruleSet.rdate(datetime(2012, 7, 1, 10, 30))

// Add another date to rruleSet
rruleSet.rdate(datetime(2012, 7, 2, 10, 30))

// Add a exclusion rrule to rruleSet
rruleSet.exrule(
  new RRule({
    freq: RRule.MONTHLY,
    count: 2,
    dtstart: datetime(2012, 3, 1, 10, 30),
  })
)

// Add a exclusion date to rruleSet
rruleSet.exdate(datetime(2012, 5, 1, 10, 30))

// Get all occurrence dates (Date instances):
rruleSet.all()[
  ('2012-02-01T10:30:00.000Z',
  '2012-05-01T10:30:00.000Z',
  '2012-07-01T10:30:00.000Z',
  '2012-07-02T10:30:00.000Z')
]

// Get a slice:
rruleSet.between(datetime(2012, 2, 1), datetime(2012, 6, 2))[
  ('2012-05-01T10:30:00.000Z', '2012-07-01T10:30:00.000Z')
]

// To string
rruleSet.valueOf()[
  ('DTSTART:20120201T023000Z',
  'RRULE:FREQ=MONTHLY;COUNT=5',
  'RDATE:20120701T023000Z,20120702T023000Z',
  'EXRULE:FREQ=MONTHLY;COUNT=2',
  'EXDATE:20120601T023000Z')
]

// To string
rruleSet.toString()
;('["DTSTART:20120201T023000Z","RRULE:FREQ=MONTHLY;COUNT=5","RDATE:20120701T023000Z,20120702T023000Z","EXRULE:FREQ=MONTHLY;COUNT=2","EXDATE:20120601T023000Z"]')

rrulestr:

// Parse a RRule string, return a RRule object
rrulestr('DTSTART:20120201T023000Z\nRRULE:FREQ=MONTHLY;COUNT=5')

// Parse a RRule string, return a RRuleSet object
rrulestr('DTSTART:20120201T023000Z\nRRULE:FREQ=MONTHLY;COUNT=5', {
  forceset: true,
})

// Parse a RRuleSet string, return a RRuleSet object
rrulestr(
  'DTSTART:20120201T023000Z\nRRULE:FREQ=MONTHLY;COUNT=5\nRDATE:20120701T023000Z,20120702T023000Z\nEXRULE:FREQ=MONTHLY;COUNT=2\nEXDATE:20120601T023000Z'
)

Important: Use UTC dates

Dates in JavaScript are tricky. RRule tries to support as much flexibility as possible without adding any large required 3rd party dependencies, but that means we also have some special rules.

By default, RRule deals in "floating" times or UTC timezones. If you want results in a specific timezone, RRule also provides timezone support. Either way, JavaScript's built-in "timezone" offset tends to just get in the way, so this library simply doesn't use it at all. All times are returned with zero offset, as though it didn't exist in JavaScript.

The bottom line is the returned "UTC" dates are always meant to be interpreted as dates in your local timezone. This may mean you have to do additional conversion to get the "correct" local time with offset applied.

For this reason, it is highly recommended to use timestamps in UTC eg. new Date(Date.UTC(...)). Returned dates will likewise be in UTC (except on Chrome, which always returns dates with a timezone offset). It's recommended to use the provided datetime helper, which creates dates in the correct format using a 1-based month.

For example:

// local machine zone is America/Los_Angeles
const rule = RRule.fromString(
  "DTSTART;TZID=America/Denver:20181101T190000;\n"
  + "RRULE:FREQ=WEEKLY;BYDAY=MO,WE,TH;INTERVAL=1;COUNT=3"
)
rule.all()

[ 2018-11-01T18:00:00.000Z,
  2018-11-05T18:00:00.000Z,
  2018-11-07T18:00:00.000Z ]
// Even though the given offset is `Z` (UTC), these are local times, not UTC times.
// Each of these this is the correct local Pacific time of each recurrence in
// America/Los_Angeles when it is 19:00 in America/Denver, including the DST shift.

// You can get the local components by using the getUTC* methods eg:
date.getUTCDate() // --> 1
date.getUTCHours() // --> 18

If you want to get the same times in true UTC, you may do so eg. using Luxon:

rule.all().map(date =>
DateTime.fromJSDate(date)
  .toUTC()
  .setZone('local', { keepLocalTime: true })
  .toJSDate()
)

[ 2018-11-02T01:00:00.000Z,
  2018-11-06T02:00:00.000Z,
  2018-11-08T02:00:00.000Z ]
// These times are in true UTC; you can see the hours shift

For more examples see python-dateutil documentation.


Timezone Support

Rrule also supports use of the TZID parameter in the RFC using the Intl API. Support matrix for the Intl API applies. If you need to support additional environments, please consider using a polyfill.

Example with TZID:

new RRule({
  dtstart: datetime(2018, 2, 1, 10, 30),
  count: 1,
  tzid: 'Asia/Tokyo',
}).all()[
  // assuming the system timezone is set to America/Los_Angeles, you get:
  '2018-01-31T17:30:00.000Z'
]
// which is the time in Los Angeles when it's 2018-02-01T10:30:00 in Tokyo.

Whether or not you use the TZID param, make sure to only use JS Date objects that are represented in UTC to avoid unexpected timezone offsets being applied, for example:

// WRONG: Will produce dates with TZ offsets added
new RRule({
  freq: RRule.MONTHLY,
  dtstart: new Date(2018, 1, 1, 10, 30),
  until: new Date(2018, 2, 31),
}).all()[('2018-02-01T18:30:00.000Z', '2018-03-01T18:30:00.000Z')]

// RIGHT: Will produce dates with recurrences at the correct time
new RRule({
  freq: RRule.MONTHLY,
  dtstart: datetime(2018, 2, 1, 10, 30),
  until: datetime(2018, 3, 31),
}).all()[('2018-02-01T10:30:00.000Z', '2018-03-01T10:30:00.000Z')]

API

RRule Constructor

new RRule(options[, noCache=false])

The options argument mostly corresponds to the properties defined for RRULE in the iCalendar RFC. Only freq is required.

OptionDescription
freq

(required) One of the following constants:

  • RRule.YEARLY
  • RRule.MONTHLY
  • RRule.WEEKLY
  • RRule.DAILY
  • RRule.HOURLY
  • RRule.MINUTELY
  • RRule.SECONDLY
dtstartThe recurrence start. Besides being the base for the recurrence, missing parameters in the final recurrence instances will also be extracted from this date. If not given, new Date will be used instead. **IMPORTANT:** See the discussion under timezone support
intervalThe interval between each freq iteration. For example, when using RRule.YEARLY, an interval of 2 means once every two years, but with RRule.HOURLY, it means once every two hours. The default interval is 1.
wkstThe week start day. Must be one of the RRule.MO, RRule.TU, RRule.WE constants, or an integer, specifying the first day of the week. This will affect recurrences based on weekly periods. The default week start is RRule.MO.
countHow many occurrences will be generated.
untilIf given, this must be a Date instance, that will specify the limit of the recurrence. If a recurrence instance happens to be the same as the Date instance given in the until argument, this will be the last occurrence.
tzidIf given, this must be a IANA string recognized by the Intl API. See discussion under Timezone support.
bysetposIf given, it must be either an integer, or an array of integers, positive or negative. Each given integer will specify an occurrence number, corresponding to the nth occurrence of the rule inside the frequency period. For example, a bysetpos of -1 if combined with a RRule.MONTHLY frequency, and a byweekday of (RRule.MO, RRule.TU, RRule.WE, RRule.TH, RRule.FR), will result in the last work day of every month.
bymonthIf given, it must be either an integer, or an array of integers, meaning the months to apply the recurrence to.
bymonthdayIf given, it must be either an integer, or an array of integers, meaning the month days to apply the recurrence to.
byyeardayIf given, it must be either an integer, or an array of integers, meaning the year days to apply the recurrence to.
byweeknoIf given, it must be either an integer, or an array of integers, meaning the week numbers to apply the recurrence to. Week numbers have the meaning described in ISO8601, that is, the first week of the year is that containing at least four days of the new year.
byweekdayIf given, it must be either an integer (0 == RRule.MO), an array of integers, one of the weekday constants (RRule.MO, RRule.TU, etc), or an array of these constants. When given, these variables will define the weekdays where the recurrence will be applied. It's also possible to use an argument n for the weekday instances, which will mean the nth occurrence of this weekday in the period. For example, with RRule.MONTHLY, or with RRule.YEARLY and BYMONTH, using RRule.FR.nth(+1) or RRule.FR.nth(-1) in byweekday will specify the first or last friday of the month where the recurrence happens. Notice that the RFC documentation, this is specified as BYDAY, but was renamed to avoid the ambiguity of that argument.
byhourIf given, it must be either an integer, or an array of integers, meaning the hours to apply the recurrence to.
byminuteIf given, it must be either an integer, or an array of integers, meaning the minutes to apply the recurrence to.
bysecondIf given, it must be either an integer, or an array of integers, meaning the seconds to apply the recurrence to.
byeasterThis is an extension to the RFC specification which the Python implementation provides. Not implemented in the JavaScript version.

noCache: Set to true to disable caching of results. If you will use the same rrule instance multiple times, enabling caching will improve the performance considerably. Enabled by default.

See also python-dateutil documentation.


Instance properties

rule.options

Processed options applied to the rule. Includes default options (such us wkstart). Currently, rule.options.byweekday isn't equal to rule.origOptions.byweekday (which is an inconsistency).

rule.origOptions

The original options argument passed to the constructor.


Occurrence Retrieval Methods

RRule.prototype.all([iterator])

Returns all dates matching the rule. It is a replacement for the iterator protocol this class implements in the Python version.

As rules without until or count represent infinite date series, you can optionally pass iterator, which is a function that is called for each date matched by the rule. It gets two parameters date (the Date instance being added), and i (zero-indexed position of date in the result). Dates are being added to the result as long as the iterator returns true. If a false-y value is returned, date isn't added to the result and the iteration is interrupted (possibly prematurely).

rule.all()[
  ('2012-02-01T10:30:00.000Z',
  '2012-05-01T10:30:00.000Z',
  '2012-07-01T10:30:00.000Z',
  '2012-07-02T10:30:00.000Z')
]

rule.all(function (date, i) {
  return i < 2
})[('2012-02-01T10:30:00.000Z', '2012-05-01T10:30:00.000Z')]

RRule.prototype.between(after, before, inc=false [, iterator])

Returns all the occurrences of the rrule between after and before. The inc keyword defines what happens if after and/or before are themselves occurrences. With inc == true, they will be included in the list, if they are found in the recurrence set.

Optional iterator has the same function as it has with RRule.prototype.all().

rule.between(datetime(2012, 8, 1), datetime(2012, 9, 1))[
  ('2012-08-27T10:30:00.000Z', '2012-08-31T10:30:00.000Z')
]

RRule.prototype.before(dt, inc=false)

Returns the last recurrence before the given Date instance. The inc argument defines what happens if dt is an occurrence. With inc == true, if dt itself is an occurrence, it will be returned.

RRule.prototype.after(dt, inc=false)

Returns the first recurrence after the given Date instance. The inc argument defines what happens if dt is an occurrence. With inc == true, if dt itself is an occurrence, it will be returned.

See also python-dateutil documentation.


iCalendar RFC String Methods

RRule.prototype.toString()

Returns a string representation of the rule as per the iCalendar RFC. Only properties explicitly specified in options are included:

rule.toString()
;('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;INTERVAL=5;UNTIL=20130130T230000Z;BYDAY=MO,FR')

rule.toString() == RRule.optionsToString(rule.origOptions)
true

RRule.optionsToString(options)

Converts options to iCalendar RFC RRULE string:

// Get full a string representation of all options,
// including the default and inferred ones.
RRule.optionsToString(rule.options)
;('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;INTERVAL=5;WKST=0;UNTIL=20130130T230000Z;BYDAY=MO,FR;BYHOUR=10;BYMINUTE=30;BYSECOND=0')

// Cherry-pick only some options from an rrule:
RRule.optionsToString({
  freq: rule.options.freq,
  dtstart: rule.options.dtstart,
})
;('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;')

RRule.fromString(rfcString)

Constructs an RRule instance from a complete rfcString:

var rule = RRule.fromString('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY;')

// This is equivalent
var rule = new RRule(
  RRule.parseString('DTSTART:20120201T093000Z\nRRULE:FREQ=WEEKLY')
)

RRule.parseString(rfcString)

Only parse RFC string and return options.

var options = RRule.parseString('FREQ=DAILY;INTERVAL=6')
options.dtstart = datetime(2000, 2, 1)
var rule = new RRule(options)

Natural Language Text Methods

These methods provide an incomplete support for text–RRule and RRule–text conversion. You should test them with your input to see whether the result is acceptable.

RRule.prototype.toText([gettext, [language]])

Returns a textual representation of rule. The gettext callback, if provided, will be called for each text token and its return value used instead. The optional language argument is a language definition to be used (defaults to rrule/nlp.js:ENGLISH).

var rule = new RRule({
  freq: RRule.WEEKLY,
  count: 23,
})
rule.toText()
;('every week for 23 times')

RRule.prototype.isFullyConvertibleToText()

Provides a hint on whether all the options the rule has are convertible to text.

RRule.fromText(text[, language])

Constructs an RRule instance from text.

rule = RRule.fromText('every day for 3 times')

RRule.parseText(text[, language])

Parse text into options:

options = RRule.parseText('every day for 3 times')
// {freq: 3, count: "3"}
options.dtstart = datetime(2000, 2, 1)
var rule = new RRule(options)

RRuleSet Constructor

new RRuleSet([(noCache = false)])

The RRuleSet instance allows more complex recurrence setups, mixing multiple rules, dates, exclusion rules, and exclusion dates.

Default noCache argument is false, caching of results will be enabled, improving performance of multiple queries considerably.

RRuleSet.prototype.rrule(rrule)

Include the given rrule instance in the recurrence set generation.

RRuleSet.prototype.rdate(dt)

Include the given datetime instance in the recurrence set generation.

RRuleSet.prototype.exrule(rrule)

Include the given rrule instance in the recurrence set exclusion list. Dates which are part of the given recurrence rules will not be generated, even if some inclusive rrule or rdate matches them. NOTE: EXRULE has been (deprecated in RFC 5545)[https://icalendar.org/iCalendar-RFC-5545/a-3-deprecated-features.html] and does not support a DTSTART property.

RRuleSet.prototype.exdate(dt)

Include the given datetime instance in the recurrence set exclusion list. Dates included that way will not be generated, even if some inclusive rrule or rdate matches them.

RRuleSet.prototype.tzid(tz?)

Sets or overrides the timezone identifier. Useful if there are no rrules in this RRuleSet and thus no DTSTART.

RRuleSet.prototype.all([iterator])

Same as RRule.prototype.all.

RRuleSet.prototype.between(after, before, inc=false [, iterator])

Same as RRule.prototype.between.

RRuleSet.prototype.before(dt, inc=false)

Same as RRule.prototype.before.

RRuleSet.prototype.after(dt, inc=false)

Same as RRule.prototype.after.

RRuleSet.prototype.rrules()

Get list of included rrules in this recurrence set.

RRuleSet.prototype.exrules()

Get list of excluded rrules in this recurrence set.

RRuleSet.prototype.rdates()

Get list of included datetimes in this recurrence set.

RRuleSet.prototype.exdates()

Get list of excluded datetimes in this recurrence set.


rrulestr Function

rrulestr(rruleStr[, options])

The rrulestr function is a parser for RFC-like syntaxes. The string passed as parameter may be a multiple line string, a single line string, or just the RRULE property value.

Additionally, it accepts the following keyword arguments:

cache If True, the rruleset or rrule created instance will cache its results. Default is not to cache.

dtstart If given, it must be a datetime instance that will be used when no DTSTART property is found in the parsed string. If it is not given, and the property is not found, datetime.now() will be used instead.

unfold If set to True, lines will be unfolded following the RFC specification. It defaults to False, meaning that spaces before every line will be stripped.

forceset If set to True a rruleset instance will be returned, even if only a single rule is found. The default is to return an rrule if possible, and an rruleset if necessary.

compatible If set to True, the parser will operate in RFC-compatible mode. Right now it means that unfold will be turned on, and if a DTSTART is found, it will be considered the first recurrence instance, as documented in the RFC.

tzid If given, it must be a string that will be used when no TZID property is found in the parsed string. If it is not given, and the property is not found, 'UTC' will be used by default.


Differences From iCalendar RFC

  • RRule has no byday keyword. The equivalent keyword has been replaced by the byweekday keyword, to remove the ambiguity present in the original keyword.
  • Unlike documented in the RFC, the starting datetime, dtstart, is not the first recurrence instance, unless it does fit in the specified rules. This is in part due to this project being a port of python-dateutil, which has the same non-compliant functionality. Note that you can get the original behavior by using a RRuleSet and adding the dtstart as an rdate.
var rruleSet = new RRuleSet()
var start = datetime(2012, 2, 1, 10, 30)

// Add a rrule to rruleSet
rruleSet.rrule(
  new RRule({
    freq: RRule.MONTHLY,
    count: 5,
    dtstart: start,
  })
)

// Add a date to rruleSet
rruleSet.rdate(start)
  • Unlike documented in the RFC, every keyword is valid on every frequency (the RFC documents that byweekno is only valid on yearly frequencies, for example).

Development

rrule.js is implemented in Typescript. It uses JavaScript Standard Style coding style.

To run the code, checkout this repository and run:

$ yarn

To run the tests, run:

$ yarn test

To build files for distribution, run:

$ yarn build

Download Details:

Author: jakubroztocil
Source Code: https://github.com/jakubroztocil/rrule 
License: View license

#typescript #javascript #library #calendar 

Bella Garvin

Bella Garvin

1623555413

Top 10 Dating App Development Companies 2021-22 - ArcticStartup

I have done some analysis and collected the world-best top 10 dating app development companies which you can choose to create a dating app like Tinder.

#dating app development #dating app development usa #dating app developer #dating app development company #dating app development services #dating mobile app developer

Jones Brianna

Jones Brianna

1625029874

Dating App Development | Dating App Development Company

This is image title

The online dating section has improved like nevermore previously and has impeccable expectations to develop additional. It has converted the first channel for reaching people as per their likes adopted as per the statistics. With such large interest, company proprietors are looking to spend in this division. If you are one such practitioner attending to make earnings by holding on to dating app development, you must be questioning, how much does it Cost to Develop a Dating App like Mingle2.

What’s Mingle2?

It is a location-based app that has a tremendous database of users and is extremely prevalent beyond the earth. The principal purpose for its reputation is its capability to offer different and manageable characteristics trimming over the opposition. Just register to the app with uncomplicated moves to start gathering, chattering, dating and swinging out with personalities of your devotions. Then the app has a reason to combine singles with satisfaction. A meaningful amount of people have been collecting the advantages of Mingle2 by developing powerful relationships and creating impactful considerations as the dating trend expands beyond the nation.

As the modern young contemporaries are going gaga above dating apps, the Mingle2 app has converted one of the foremost players in the business. The combinations have produced productive associations, connections, and compatibilities with long-term servitude. It helps to completely make new friends, by dating or simply gathering and conversing online which was never so regular in earlier days.

A freakish characteristic of Mingle 2 dating app is that there will be no boundaries to the communications like other equivalents. Even though there may be different dating apps, Mingle2 offers an unlimited possibility for improving the understanding to find cooperative people in nearby locations.

Why are Dating Apps Widespread Across the Globe?

A major cause for the prevalence of dating apps is the opportunity to separate people before reaching them in character. Ere this, people had to go blindfolded while they match any person on their first date. This is a great concern particularly for women going to meet newcomers.
One more huge appearance to review is the practical landscape of social media app development. Forward with submitting a fitting meeting, the dating app allows simple and genuine service. Consequently, apps with exceptional characteristics along with easy navigable UI have been useful in the competing market.

How Much Does it Cost to Make an App like Mingle2?

If you are contemplating producing an app like Mingle2, then the initial point that happens to your brain will be How much does it cost to make an app like Mingle2? The fact is that it will never be a specific quantity that suits every project. Some key features determine the cost of developing an app like Mingle2.

App Size

The development of an app like Mingle2 may involve a different variety of characteristics and functionalities. So, with the enrichment in these components, there will also be augmentation in app size. Hence, to skirt improving the extent of the app due to irrelevant embodiments,

App Design

It is reliable that users view for appealing UI, but not ostentatious forms more than functionalities. The design should be manageable, navigable yet occupying to continue the user’s enthusiasm for greater. Excellent designs will enhance the abundance but also come with an expanded cost of development.

Type and Number of Platforms

With the enhanced opposition in the business, any app needs to prepare the pattern for larger. An essential action in performing this to improve the app for optimal platforms as per customer proximity. Creating a native app will offer you abundance but will require more than composite apps that have a unique code base for various platforms.

Final thoughts

With more characters going the online way, mobile dating apps like Tinder which were already successful will go still additional in regulation. But it is necessary to connect with a strong mobile app development company in India like Mobiweb Technologies. With a team of proficient app builders, they hold an edge over the opponents for producing a grand end product according to your specifications. We are also experts in fantasy sports app development services.

#dating app development #dating app development usa #dating app developer #dating app solution #dating app development company

How much does it cost to build an iPhone dating app?

The dating app market is overflowing. And the demand for dating apps among consumers is far from declining. Smart phones gave a new life to online dating that is the only reason why dating mobile application is important. More and more people are going online to find a life partner. That is why creating apps, chats, sites of a dating background have become extremely popular these days.

AppClues Infotech is one of the best dating mobile app development company among all offer services on various platforms at competitive prices. We specialize in iPhone app development for various industries not only in dating app. We design & develop custom feature rich apps for our clients which help them to take their business at next level at competitive prices that suit your budget perfectly.

We Offer iPhone App Development Services Like:

  • Custom iPhone Apps Development
  • iPhone UX/UI Designing
  • iPhone Ecommerce Apps
  • iPhone Healthcare Apps
  • iPhone Social Networking Apps
  • iPhone Dating Apps
  • iPhone Support & Maintenance
  • iPhone App Testing / Portability

We have a dedicated team of developers who have developed custom applications for the dating industry. The highly experienced developers provide the most tailored and robust solutions to the clients. We have successfully designed and developed dating apps to our client’s satisfaction. We put all intellectual and technical skills to provide you with the best Dating App ever.

We generally charge in the range rates of $5000 to $45,000 which depends on your requirement. We shall decide on the basis of their requirement, app features, experience level of the developer and many other factors.

Let’s Get Started your project

REQUEST A QUOTE

#how much does it cost to make a dating app #how to create a dating app and how much does it cost #dating app development company #top dating app development company in usa #custom dating app development services #online dating app solution development company

Jones Brianna

Jones Brianna

1611912382

Dating App Development | Dating App Development Company

https://www.mobiwebtech.com/dating-app-development/

Mobiweb Technologies is a leading dating app development company that builds exclusive dating apps. We develop dating apps with features like find profile match, dating partner suggestion, location-based dating app, and more to deliver an amazing online dating experience.

#dating app developer #dating app development usa #dating app development company #dating mobile app development #dating mobile app developer