Added more quarter functions (#14)

Co-authored-by: Rob Blackbourn <rob.blackbourn@gmail.com>

src/endOfQuarter.ts

@@ -0,0 +1,21 @@
+import { tzLocal } from './LocalTimezone'
+import { Timezone } from './Timezone'
+import { daysInMonth } from './daysInMonth'
+import { quarterOfYear } from './quarterOfYear'
+
+/**
+ * Find the last moment of the quarter.
+ *
+ * @category Anchors
+ *
+ * @param date A date
+ * @param tz An optional timezone. Defaults to the local timezone.
+ * @returns The last moment of the quarter.
+ */
+export function endOfQuarter(date: Date, tz: Timezone = tzLocal): Date {
+  const quarter = quarterOfYear(date, tz)
+  const monthIndex = 3 * (quarter - 1) + 2
+  const year = tz.year(date)
+  const day = daysInMonth(year, monthIndex)
+  return tz.makeDate(year, monthIndex, day, 23, 59, 59, 999)
+}

src/findEndOfMonthIndex.ts

@@ -1,4 +1,4 @@
-import { isEndOfMonth } from './isEndOfMonth'
+import { isLastDayOfMonth } from './isLastDayOfMonth'
 import { tzLocal } from './LocalTimezone'
 import { Timezone } from './Timezone'
 
@@ -13,5 +13,5 @@ export function findEndOfMonthIndex(
   dates: Date[],
   tz: Timezone = tzLocal
 ): number {
-  return dates.findIndex(date => isEndOfMonth(date, tz))
+  return dates.findIndex(date => isLastDayOfMonth(date, tz))
 }

src/findLastEndOfMonthIndex.ts

@@ -1,4 +1,4 @@
-import { isEndOfMonth } from './isEndOfMonth'
+import { isLastDayOfMonth } from './isLastDayOfMonth'
 import { tzLocal } from './LocalTimezone'
 import { Timezone } from './Timezone'
 import { findLastIndex } from './utils'
@@ -14,5 +14,5 @@ export function findLastEndOfMonthIndex(
   dates: Date[],
   tz: Timezone = tzLocal
 ): number {
-  return findLastIndex(dates, date => isEndOfMonth(date, tz))
+  return findLastIndex(dates, date => isLastDayOfMonth(date, tz))
 }

src/index.ts

@@ -37,6 +37,7 @@ export { endOfDay } from './endOfDay'
 export { endOfHour } from './endOfHour'
 export { endOfMinute } from './endOfMinute'
 export { endOfMonth } from './endOfMonth'
+export { endOfQuarter } from './endOfQuarter'
 export { endOfSecond } from './endOfSecond'
 export { endOfToday } from './endOfToday'
 export { endOfWeek } from './endOfWeek'
@@ -58,12 +59,14 @@ export { isDateEqual } from './isDateEqual'
 export { isDateNotEqual } from './isDateNotEqual'
 export { isDateOnOrAfter } from './isDateOnOrAfter'
 export { isDateOnOrBefore } from './isDateOnOrBefore'
-export { isEndOfMonth } from './isEndOfMonth'
+export { isLastDayOfMonth } from './isLastDayOfMonth'
+export { isLastDayOfQuarter } from './isLastDayOfQuarter'
 export { isLeapYear } from './isLeapYear'
 export { isoWeekDate } from './isoWeekDate'
 export { isoWeekOfYear } from './isoWeekOfYear'
 export { isValidDate } from './isValidDate'
 export { lastDayOfMonth } from './lastDayOfMonth'
+export { lastDayOfQuarter } from './lastDayOfQuarter'
 export { lastDayOfWeek } from './lastDayOfWeek'
 export { lastDayOfWeekday } from './lastDayOfWeekday'
 export { lastDayOfYear } from './lastDayOfYear'
@@ -89,6 +92,7 @@ export { startOfHour } from './startOfHour'
 export { startOfISOWeek } from './startOfISOWeek'
 export { startOfMinute } from './startOfMinute'
 export { startOfMonth } from './startOfMonth'
+export { startOfQuarter } from './startOfQuarter'
 export { startOfSecond } from './startOfSecond'
 export { startOfWeek } from './startOfWeek'
 export { startOfWeekday } from './startOfWeekday'

src/isEndOfMonth.ts → src/isLastDayOfMonth.ts

@@ -11,11 +11,6 @@ import { Timezone } from './Timezone'
  * @param tz An optional timezone. Defaults to the local timezone.
  * @returns True if the date is the last day of the month.
  */
-export function isEndOfMonth(date: Date, tz: Timezone = tzLocal): boolean {
-  const { year, monthIndex, day } = tz.dateParts(date, {
-    year: true,
-    monthIndex: true,
-    day: true
-  })
-  return day === daysInMonth(year, monthIndex)
+export function isLastDayOfMonth(date: Date, tz: Timezone = tzLocal): boolean {
+  return tz.day(date) === daysInMonth(tz.year(date), tz.monthIndex(date))
 }

src/isLastDayOfQuarter.ts

@@ -0,0 +1,21 @@
+import { isDateEqual } from './isDateEqual'
+import { lastDayOfQuarter } from './lastDayOfQuarter'
+import { tzLocal } from './LocalTimezone'
+import { Timezone } from './Timezone'
+
+/**
+ * Check if the date is the last day of the quarter.
+ *
+ * @category Calendars
+ *
+ * @param date The date to check.
+ * @param tz An optional timezone. Defaults to the local timezone.
+ * @returns True if the date is the last day of the quarter.
+ */
+export function isLastDayOfQuarter(
+  date: Date,
+  tz: Timezone = tzLocal
+): boolean {
+  const end = lastDayOfQuarter(date, tz)
+  return isDateEqual(date, end)
+}

src/lastDayOfQuarter.ts

@@ -0,0 +1,21 @@
+import { tzLocal } from './LocalTimezone'
+import { Timezone } from './Timezone'
+import { daysInMonth } from './daysInMonth'
+import { quarterOfYear } from './quarterOfYear'
+
+/**
+ * Find the last day of the quarter.
+ *
+ * @category Anchors
+ *
+ * @param date The start date.
+ * @param tz An optional timezone. Defaults to the local timezone.
+ * @returns A date which is the last day of the quarter.
+ */
+export function lastDayOfQuarter(date: Date, tz: Timezone = tzLocal): Date {
+  const quarter = quarterOfYear(date, tz)
+  const monthIndex = 3 * (quarter - 1) + 2
+  const year = tz.year(date)
+  const day = daysInMonth(year, monthIndex)
+  return tz.makeDate(year, monthIndex, day)
+}

src/startOfMonth.ts

@@ -2,7 +2,7 @@ import { tzLocal } from './LocalTimezone'
 import { Timezone } from './Timezone'
 
 /**
- * Find the start of the months for a given date.
+ * Find the start of the month for a given date.
  *
  * @category Anchors
  *

src/startOfQuarter.ts

@@ -0,0 +1,18 @@
+import { tzLocal } from './LocalTimezone'
+import { Timezone } from './Timezone'
+import { quarterOfYear } from './quarterOfYear'
+
+/**
+ * Find the start of the quarter for a given date.
+ *
+ * @category Anchors
+ *
+ * @param date The date.
+ * @param tz An optional timezone. Defaults to the local timezone.
+ * @returns The start of the quarter.
+ */
+export function startOfQuarter(date: Date, tz: Timezone = tzLocal): Date {
+  const quarter = quarterOfYear(date, tz)
+  const monthIndex = 3 * (quarter - 1)
+  return tz.makeDate(tz.year(date), monthIndex, 1)
+}

test/endOfQuarter.test.ts

@@ -0,0 +1,31 @@
+import {
+  IANATimezone,
+  dataToTimezoneOffset,
+  endOfQuarter,
+  tzLocal,
+  tzUtc
+} from '../src'
+import chicagoTzData from '@jetblack/tzdata/dist/latest/America/Chicago.json'
+import tokyoTzData from '@jetblack/tzdata/dist/latest/Asia/Tokyo.json'
+
+describe('endOfQuarter', () => {
+  const tzChicago = new IANATimezone(
+    'America/Chicago',
+    chicagoTzData.map(dataToTimezoneOffset)
+  )
+  const tzTokyo = new IANATimezone(
+    'Asia/Tokyo',
+    tokyoTzData.map(dataToTimezoneOffset)
+  )
+
+  for (const tz of [tzUtc, tzLocal, tzChicago, tzTokyo]) {
+    describe(tz.name, () => {
+      it('should find the last moment of the quarter', () => {
+        const date = tz.makeDate(2000, 0, 1)
+        const actual = endOfQuarter(date, tz)
+        const expected = tz.makeDate(2000, 2, 31, 23, 59, 59, 999)
+        expect(tz.toISOString(actual)).toBe(tz.toISOString(expected))
+      })
+    })
+  }
+})

test/isEndOfMonth.test.ts → test/isLastDayOfMonth.test.ts

@@ -1,14 +1,14 @@
 import {
   IANATimezone,
   dataToTimezoneOffset,
-  isEndOfMonth,
+  isLastDayOfMonth,
   tzLocal,
   tzUtc
 } from '../src'
 import chicagoTzData from '@jetblack/tzdata/dist/latest/America/Chicago.json'
 import tokyoTzData from '@jetblack/tzdata/dist/latest/Asia/Tokyo.json'
 
-describe('isEndOfMonth', () => {
+describe('isLastDayOfMonth', () => {
   const tzChicago = new IANATimezone(
     'America/Chicago',
     chicagoTzData.map(dataToTimezoneOffset)
@@ -22,27 +22,27 @@ describe('isEndOfMonth', () => {
     describe(tz.name, () => {
       it('should know 30 January is not the end of the month', () => {
         const date = tz.makeDate(2008, 0, 30)
-        expect(isEndOfMonth(date, tz)).toBeFalsy()
+        expect(isLastDayOfMonth(date, tz)).toBeFalsy()
       })
 
-      it('should know 31 January is not the end of the month', () => {
+      it('should know 31 January is the end of the month', () => {
         const date = tz.makeDate(2008, 0, 31)
-        expect(isEndOfMonth(date, tz)).toBeTruthy()
+        expect(isLastDayOfMonth(date, tz)).toBeTruthy()
       })
 
       it('should know 28 February 2008 is not the end of the month because 2008 is a leap year', () => {
         const date = tz.makeDate(2008, 1, 28)
-        expect(isEndOfMonth(date, tz)).toBeFalsy()
+        expect(isLastDayOfMonth(date, tz)).toBeFalsy()
       })
 
       it('should know 29 February 2008 is the end of the month because 2008 is a leap year', () => {
         const date = tz.makeDate(2008, 1, 29)
-        expect(isEndOfMonth(date, tz)).toBeTruthy()
+        expect(isLastDayOfMonth(date, tz)).toBeTruthy()
       })
 
       it('should know 28 February 2009 is the end of the month because 2008 is not a leap year', () => {
         const date = tz.makeDate(2009, 1, 28)
-        expect(isEndOfMonth(date, tz)).toBeTruthy()
+        expect(isLastDayOfMonth(date, tz)).toBeTruthy()
       })
     })
   }

test/isLastDayOfQuarter.test.ts

@@ -0,0 +1,34 @@
+import {
+  IANATimezone,
+  dataToTimezoneOffset,
+  isLastDayOfQuarter,
+  tzLocal,
+  tzUtc
+} from '../src'
+import chicagoTzData from '@jetblack/tzdata/dist/latest/America/Chicago.json'
+import tokyoTzData from '@jetblack/tzdata/dist/latest/Asia/Tokyo.json'
+
+describe('isLastDayOfQuarter', () => {
+  const tzChicago = new IANATimezone(
+    'America/Chicago',
+    chicagoTzData.map(dataToTimezoneOffset)
+  )
+  const tzTokyo = new IANATimezone(
+    'Asia/Tokyo',
+    tokyoTzData.map(dataToTimezoneOffset)
+  )
+
+  for (const tz of [tzUtc, tzLocal, tzChicago, tzTokyo]) {
+    describe(tz.name, () => {
+      it('should know 30 January is not the end of the quarter', () => {
+        const date = tz.makeDate(2008, 0, 30)
+        expect(isLastDayOfQuarter(date, tz)).toBeFalsy()
+      })
+
+      it('should know 31 March is the end of the month', () => {
+        const date = tz.makeDate(2008, 2, 31)
+        expect(isLastDayOfQuarter(date, tz)).toBeTruthy()
+      })
+    })
+  }
+})

test/lastDayOfQuarter.test.ts

@@ -0,0 +1,30 @@
+import {
+  IANATimezone,
+  dataToTimezoneOffset,
+  lastDayOfQuarter,
+  tzLocal,
+  tzUtc
+} from '../src'
+import chicagoTzData from '@jetblack/tzdata/dist/latest/America/Chicago.json'
+import tokyoTzData from '@jetblack/tzdata/dist/latest/Asia/Tokyo.json'
+
+describe('lastDayOfQuarter', () => {
+  const tzChicago = new IANATimezone(
+    'America/Chicago',
+    chicagoTzData.map(dataToTimezoneOffset)
+  )
+  const tzTokyo = new IANATimezone(
+    'Asia/Tokyo',
+    tokyoTzData.map(dataToTimezoneOffset)
+  )
+
+  for (const tz of [tzUtc, tzLocal, tzChicago, tzTokyo]) {
+    describe(tz.name, () => {
+      it('should find the last day of the quarter', () => {
+        const actual = lastDayOfQuarter(tz.makeDate(2000, 0, 1), tz)
+        const expected = tz.makeDate(2000, 2, 31)
+        expect(tz.toISOString(actual)).toBe(tz.toISOString(expected))
+      })
+    })
+  }
+})

test/startOfQuarter.test.ts

@@ -0,0 +1,38 @@
+import {
+  IANATimezone,
+  dataToTimezoneOffset,
+  startOfQuarter,
+  tzLocal,
+  tzUtc
+} from '../src'
+import chicagoTzData from '@jetblack/tzdata/dist/latest/America/Chicago.json'
+import tokyoTzData from '@jetblack/tzdata/dist/latest/Asia/Tokyo.json'
+
+describe('startOfQuarter', () => {
+  const tzChicago = new IANATimezone(
+    'America/Chicago',
+    chicagoTzData.map(dataToTimezoneOffset)
+  )
+  const tzTokyo = new IANATimezone(
+    'Asia/Tokyo',
+    tokyoTzData.map(dataToTimezoneOffset)
+  )
+
+  for (const tz of [tzUtc, tzLocal, tzChicago, tzTokyo]) {
+    describe(tz.name, () => {
+      it('should return the start of the quarters', () => {
+        const date = tz.makeDate(2014, 8, 2, 2, 11, 55, 664)
+        const actual = startOfQuarter(date, tz)
+        const expected = tz.makeDate(2014, 6, 1)
+        expect(tz.toISOString(actual)).toBe(tz.toISOString(expected))
+      })
+
+      it('should not change date', () => {
+        const date = tz.makeDate(2014, 6, 1)
+        const actual = startOfQuarter(date, tz)
+        const expected = tz.makeDate(2014, 6, 1)
+        expect(tz.toISOString(actual)).toBe(tz.toISOString(expected))
+      })
+    })
+  }
+})