rrule/src/nlp/index.ts

import ToText, { DateFormatter, GetText } from './totext'
import parseText from './parsetext'
import { RRule } from '../rrule'
import { Frequency } from '../types'
import ENGLISH, { Language } from './i18n'

/* !
 * rrule.js - Library for working with recurrence rules for calendar dates.
 * https://github.com/jakubroztocil/rrule
 *
 * Copyright 2010, Jakub Roztocil and Lars Schoning
 * Licenced under the BSD licence.
 * https://github.com/jakubroztocil/rrule/blob/master/LICENCE
 *
 */

/**
 *
 * Implementation of RRule.fromText() and RRule::toText().
 *
 *
 * On the client side, this file needs to be included
 * when those functions are used.
 *
 */

// =============================================================================
// fromText
// =============================================================================
/**
 * Will be able to convert some of the below described rules from
 * text format to a rule object.
 *
 *
 * RULES
 *
 * Every ([n])
 * day(s)
 * | [weekday], ..., (and) [weekday]
 * | weekday(s)
 * | week(s)
 * | month(s)
 * | [month], ..., (and) [month]
 * | year(s)
 *
 *
 * Plus 0, 1, or multiple of these:
 *
 * on [weekday], ..., (or) [weekday] the [monthday], [monthday], ... (or) [monthday]
 *
 * on [weekday], ..., (and) [weekday]
 *
 * on the [monthday], [monthday], ... (and) [monthday] (day of the month)
 *
 * on the [nth-weekday], ..., (and) [nth-weekday] (of the month/year)
 *
 *
 * Plus 0 or 1 of these:
 *
 * for [n] time(s)
 *
 * until [date]
 *
 * Plus (.)
 *
 *
 * Definitely no supported for parsing:
 *
 * (for year):
 * in week(s) [n], ..., (and) [n]
 *
 * on the [yearday], ..., (and) [n] day of the year
 * on day [yearday], ..., (and) [n]
 *
 *
 * NON-TERMINALS
 *
 * [n]: 1, 2 ..., one, two, three ..
 * [month]: January, February, March, April, May, ... December
 * [weekday]: Monday, ... Sunday
 * [nth-weekday]: first [weekday], 2nd [weekday], ... last [weekday], ...
 * [monthday]: first, 1., 2., 1st, 2nd, second, ... 31st, last day, 2nd last day, ..
 * [date]:
 * - [month] (0-31(,) ([year])),
 * - (the) 0-31.(1-12.([year])),
 * - (the) 0-31/(1-12/([year])),
 * - [weekday]
 *
 * [year]: 0000, 0001, ... 01, 02, ..
 *
 * Definitely not supported for parsing:
 *
 * [yearday]: first, 1., 2., 1st, 2nd, second, ... 366th, last day, 2nd last day, ..
 *
 * @param {String} text
 * @return {Object, Boolean} the rule, or null.
 */
const fromText = function (text: string, language: Language = ENGLISH) {
  return new RRule(parseText(text, language) || undefined)
}

const common = [
  'count',
  'until',
  'interval',
  'byweekday',
  'bymonthday',
  'bymonth',
]

ToText.IMPLEMENTED = []
ToText.IMPLEMENTED[Frequency.HOURLY] = common
ToText.IMPLEMENTED[Frequency.MINUTELY] = common
ToText.IMPLEMENTED[Frequency.DAILY] = ['byhour'].concat(common)
ToText.IMPLEMENTED[Frequency.WEEKLY] = common
ToText.IMPLEMENTED[Frequency.MONTHLY] = common
ToText.IMPLEMENTED[Frequency.YEARLY] = ['byweekno', 'byyearday'].concat(common)

// =============================================================================
// Export
// =============================================================================

const toText = function (
  rrule: RRule,
  gettext?: GetText,
  language?: Language,
  dateFormatter?: DateFormatter
) {
  return new ToText(rrule, gettext, language, dateFormatter).toString()
}

const { isFullyConvertible } = ToText

export interface Nlp {
  fromText: typeof fromText
  parseText: typeof parseText
  isFullyConvertible: typeof isFullyConvertible
  toText: typeof toText
}

export { fromText, parseText, isFullyConvertible, toText }