Add support for floating date-time and date values

src/dateutil.ts

@@ -161,7 +161,7 @@ export namespace dateutil {
     })
   }
 
-  export const timeToUntilString = function (time: number, utc = true) {
+  export const toRfc5545DateTime = function (time: number, utc = true) {
     const date = new Date(time)
     return [
       padStart(date.getUTCFullYear().toString(), 4, '0'),
@@ -175,11 +175,20 @@ export namespace dateutil {
     ].join('')
   }
 
-  export const untilStringToDate = function (until: string) {
+  export const toRfc5545Date = function (time: number) {
+    const date = new Date(time)
+    return [
+      padStart(date.getUTCFullYear().toString(), 4, '0'),
+      padStart(date.getUTCMonth() + 1, 2, '0'),
+      padStart(date.getUTCDate(), 2, '0')
+    ].join('')
+  }
+
+  export const fromRfc5545DateTime = function (dt: string) {
     const re = /^(\d{4})(\d{2})(\d{2})(T(\d{2})(\d{2})(\d{2})Z?)?$/
-    const bits = re.exec(until)
+    const bits = re.exec(dt)
 
-    if (!bits) throw new Error(`Invalid UNTIL value: ${until}`)
+    if (!bits) throw new Error(`Invalid date-time value: ${dt}`)
 
     return new Date(
       Date.UTC(
@@ -193,6 +202,21 @@ export namespace dateutil {
     )
   }
 
+  export const fromRfc5545Date = function (dt: string) {
+    const re = /^(\d{4})(\d{2})(\d{2})$/
+    const bits = re.exec(dt)
+
+    if (!bits) throw new Error(`Invalid date value: ${dt}`)
+
+    return new Date(
+      Date.UTC(
+        parseInt(bits[1], 10),
+        parseInt(bits[2], 10) - 1,
+        parseInt(bits[3], 10)
+      )
+    )
+  }
+
 }
 
 export default dateutil

src/datewithzone.ts

@@ -15,7 +15,7 @@ export class DateWithZone {
   }
 
   public toString () {
-    const datestr = dateutil.timeToUntilString(this.date.getTime(), this.isUTC)
+    const datestr = dateutil.toRfc5545DateTime(this.date.getTime(), this.isUTC)
     if (!this.isUTC) {
       return `;TZID=${this.tzid}:${datestr}`
     }

src/optionstostring.ts

@@ -1,4 +1,4 @@
-import { Options } from './types'
+import { Options, DateTimeProperty, DateTimeValue } from './types'
 import RRule, { DEFAULT_OPTIONS } from './rrule'
 import { includes, isPresent, isArray, isNumber, toArray } from './helpers'
 import { Weekday } from './weekday'
@@ -60,15 +60,35 @@ export function optionsToString (options: Partial<Options>) {
         break
 
       case 'DTSTART':
-        dtstart = buildDateTime(value, options.tzid)
+        dtstart = formatDateTime(value, options, DateTimeProperty.START)
         break
 
       case 'DTEND':
-        dtend = buildDateTime(value, options.tzid, true /* end */)
+        dtend = formatDateTime(value, options, DateTimeProperty.END)
+        break
+
+      case 'DTVALUE':
+      case 'DTFLOATING':
         break
 
       case 'UNTIL':
-        outValue = dateutil.timeToUntilString(value, !options.tzid)
+        /**
+         * From [RFC 5545](https://tools.ietf.org/html/rfc5545):
+         *
+         * 3.3.10. Recurrence Rule
+         *
+         * The value of the UNTIL rule part MUST have the same value type as the
+         * "DTSTART" property. Furthermore, if the "DTSTART" property is specified as
+         * a date with local time, then the UNTIL rule part MUST also be specified as
+         * a date with local time. If the "DTSTART" property is specified as a date
+         * with UTC time or a date with local time and time zone reference, then the
+         * UNTIL rule part MUST be specified as a date with UTC time.
+         */
+        if (options.dtvalue === DateTimeValue.DATE) {
+          outValue = dateutil.toRfc5545Date(value)
+        } else {
+          outValue = dateutil.toRfc5545DateTime(value, !options.dtfloating)
+        }
         break
 
       default:
@@ -97,10 +117,16 @@ export function optionsToString (options: Partial<Options>) {
   return [ dtstart, dtend, ruleString ].filter(x => !!x).join('\n')
 }
 
-function buildDateTime (dt?: number, tzid?: string | null, end: boolean = false) {
+function formatDateTime (dt?: number, options: Partial<Options> = {}, prop = DateTimeProperty.START) {
   if (!dt) {
     return ''
   }
-
-  return 'DT' + (end ? 'END' : 'START') + new DateWithZone(new Date(dt), tzid).toString()
+  let prefix = prop.toString()
+  if (options.dtvalue) {
+    prefix += ';VALUE=' + options.dtvalue.toString()
+  }
+  if (options.dtfloating) {
+    return prefix + ':' + dateutil.toRfc5545DateTime(dt, false)
+  }
+  return prefix + new DateWithZone(new Date(dt), options.tzid).toString()
 }

src/parsestring.ts

@@ -1,34 +1,96 @@
-import { Options, Frequency } from './types'
+import { Options, Frequency, DateTimeProperty, DateTimeValue } from './types'
 import { Weekday } from './weekday'
 import dateutil from './dateutil'
 import { Days } from './rrule'
 
 export function parseString (rfcString: string): Partial<Options> {
   const options = rfcString.split('\n').map(parseLine).filter(x => x !== null)
-  return options.reduce((acc, cur) => Object.assign(acc, cur), {}) || {}
+  /**
+   * From [RFC 5545](https://tools.ietf.org/html/rfc5545):
+   *
+   * 3.8.2.2. Date-Time End ("DTEND")
+   *
+   * The value type of this property MUST be the same as the "DTSTART" property, and its
+   * value MUST be later in time than the value of the "DTSTART" property. Furthermore,
+   * this property MUST be specified as a date with local time if and only if the
+   * "DTSTART" property is also specified as a date with local time.
+   */
+  return options.reduce((acc: Partial<Options>, cur: Partial<Options>) => {
+    let existing
+    if (cur.dtstart) {
+      if (acc.dtstart) {
+        throw new Error('Invalid rule: DTSTART must occur only once')
+      }
+      if (acc.dtend && acc.dtend.valueOf() <= cur.dtstart.valueOf()) {
+        throw new Error('Invalid rule: DTEND must be later than DTSTART')
+      }
+      existing = acc.dtend
+    }
+    if (cur.dtend) {
+      if (acc.dtend) {
+        throw new Error('Invalid rule: DTEND must occur only once')
+      }
+      if (acc.dtstart && acc.dtstart.valueOf() >= cur.dtend.valueOf()) {
+        throw new Error('Invalid rule: DTEND must be later than DTSTART')
+      }
+      existing = acc.dtstart
+    }
+    if (existing && acc.dtvalue !== cur.dtvalue) {
+      // Different value types.
+      throw new Error('Invalid rule: DTSTART and DTEND must have the same value type')
+    } else if (existing && acc.tzid !== cur.tzid) {
+      // Different timezones.
+      throw new Error('Invalid rule: DTSTART and DTEND must have the same timezone')
+    } else if (existing && acc.dtfloating !== cur.dtfloating) {
+      // Different floating types.
+      throw new Error('Invalid rule: DTSTART and DTEND must both be floating')
+    }
+    return Object.assign(acc, cur)
+  }, {}) || {}
 }
 
-export function parseDateTime (line: string, end: boolean = false) {
+export function parseDateTime (line: string, prop = DateTimeProperty.START): Partial<Options> {
   const options: Partial<Options> = {}
 
-  const dtWithZone = end
-    ? /DTEND(?:;TZID=([^:=]+?))?(?::|=)([^;\s]+)/i.exec(line)
-    : /DTSTART(?:;TZID=([^:=]+?))?(?::|=)([^;\s]+)/i.exec(line)
+  const dtWithZone = new RegExp(
+    `${prop}(?:;TZID=([^:=]+?))?(?:;VALUE=(DATE|DATE-TIME))?(?::|=)([^;\\s]+)`, 'i'
+  ).exec(line)
 
   if (!dtWithZone) {
     return options
   }
 
-  const [ _, tzid, dt ] = dtWithZone
+  const [ _, tzid, dtvalue, dt ] = dtWithZone
 
   if (tzid) {
+    if (dt.endsWith('Z')) {
+      throw new Error(`Invalid UTC date-time with timezone: ${line}`)
+    }
     options.tzid = tzid
   }
-  if (end) {
-    options.dtend = dateutil.untilStringToDate(dt)
-  } else {
-    options.dtstart = dateutil.untilStringToDate(dt)
+
+  if (dtvalue === DateTimeValue.DATE) {
+    if (prop === DateTimeProperty.START) {
+      options.dtstart = dateutil.fromRfc5545Date(dt)
+    } else {
+      options.dtend = dateutil.fromRfc5545Date(dt)
+    }
+    options.dtvalue = DateTimeValue.DATE
+    options.dtfloating = true
+  } else { // Default value type is DATE-TIME
+    if (prop === DateTimeProperty.START) {
+      options.dtstart = dateutil.fromRfc5545DateTime(dt)
+    } else {
+      options.dtend = dateutil.fromRfc5545DateTime(dt)
+    }
+    if (dtvalue) {
+      options.dtvalue = DateTimeValue.DATE_TIME
+    }
+    if (!tzid && !dt.endsWith('Z')) {
+      options.dtfloating = !tzid && !dt.endsWith('Z')
+    }
   }
+
   return options
 }
 
@@ -47,9 +109,9 @@ function parseLine (rfcString: string) {
     case 'EXRULE':
       return parseRrule(rfcString)
     case 'DTSTART':
-      return parseDateTime(rfcString)
+      return parseDateTime(rfcString, DateTimeProperty.START)
     case 'DTEND':
-      return parseDateTime(rfcString, true /* end */)
+      return parseDateTime(rfcString, DateTimeProperty.END)
     default:
       throw new Error(`Unsupported RFC prop ${key} in ${rfcString}`)
   }
@@ -95,9 +157,15 @@ function parseRrule (line: string) {
         const dtstart = parseDateTime(line)
         options.tzid = dtstart.tzid
         options.dtstart = dtstart.dtstart
+        if (dtstart.dtvalue) {
+          options.dtvalue = dtstart.dtvalue
+        }
+        if (dtstart.dtfloating) {
+          options.dtfloating = dtstart.dtfloating
+        }
         break
       case 'UNTIL':
-        options.until = dateutil.untilStringToDate(value)
+        options.until = dateutil.fromRfc5545DateTime(value)
         break
       case 'BYEASTER':
         options.byeaster = Number(value)

src/rrule.ts

@@ -5,7 +5,7 @@ import CallbackIterResult from './callbackiterresult'
 import { Language } from './nlp/i18n'
 import { Nlp } from './nlp/index'
 import { DateFormatter, GetText } from './nlp/totext'
-import { ParsedOptions, Options, Frequency, QueryMethods, QueryMethodTypes, IterResultType } from './types'
+import { ParsedOptions, Options, DateTimeValue, Frequency, QueryMethods, QueryMethodTypes, IterResultType } from './types'
 import { parseOptions, initializeOptions } from './parseoptions'
 import { parseString } from './parsestring'
 import { optionsToString } from './optionstostring'
@@ -44,6 +44,8 @@ export const DEFAULT_OPTIONS: Options = {
   freq: Frequency.YEARLY,
   dtstart: null,
   dtend: null,
+  dtvalue: DateTimeValue.DATE_TIME,
+  dtfloating: false,
   interval: 1,
   wkst: Days.MO,
   count: null,
@@ -265,7 +267,7 @@ export default class RRule implements QueryMethods {
     if (this.options.until && dt.valueOf() > this.options.until.valueOf()) {
       return false
     }
-    return dt.valueOf() >= prev.valueOf() && dt.valueOf() < (prev.valueOf() + this.duration())
+    return dt.valueOf() >= prev.valueOf() && dt.valueOf() < (prev.valueOf() + (this.duration() || 0))
   }
 
   /**

src/rruleset.ts

@@ -3,7 +3,7 @@ import dateutil from './dateutil'
 import { includes } from './helpers'
 import IterResult from './iterresult'
 import { iterSet } from './iterset'
-import { QueryMethodTypes, IterResultType } from './types'
+import { DateTimeProperty, QueryMethodTypes, IterResultType } from './types'
 import { rrulestr } from './rrulestr'
 import { optionsToString } from './optionstostring'
 
@@ -33,6 +33,7 @@ export default class RRuleSet extends RRule {
   public readonly _exdate: Date[]
 
   private _dtstart?: Date | null | undefined
+  private _dtend?: Date | null | undefined
   private _tzid?: string
 
   /**
@@ -143,6 +144,9 @@ export default class RRuleSet extends RRule {
     if (!this._rrule.length && this._dtstart) {
       result = result.concat(optionsToString({ dtstart: this._dtstart }))
     }
+    if (!this._rrule.length && this._dtend) {
+      result = result.concat(optionsToString({ dtend: this._dtend }))
+    }
 
     this._rrule.forEach(function (rrule) {
       result = result.concat(rrule.toString().split('\n'))
@@ -221,7 +225,7 @@ function rdatesToString (param: string, rdates: Date[], tzid: string | undefined
   const header = isUTC ? `${param}:` : `${param};TZID=${tzid}:`
 
   const dateString = rdates
-      .map(rdate => dateutil.timeToUntilString(rdate.valueOf(), isUTC))
+      .map(rdate => dateutil.toRfc5545DateTime(rdate.valueOf(), isUTC))
       .join(',')
 
   return `${header}${dateString}`