Fix - add and subtract when duration has undefined params

src/add/index.ts

@@ -20,7 +20,7 @@ import { Duration } from '../types'
  * |----------------|------------------------------------|
  * | years          | Amount of years to be added        |
  * | months         | Amount of months to be added       |
- * | weeks          | Amount of weeks to be added       |
+ * | weeks          | Amount of weeks to be added        |
  * | days           | Amount of days to be added         |
  * | hours          | Amount of hours to be added        |
  * | minutes        | Amount of minutes to be added      |
@@ -52,13 +52,13 @@ export default function add(
 
   if (!duration || typeof duration !== 'object') return new Date(NaN)
 
-  const years = 'years' in duration ? toInteger(duration.years) : 0
-  const months = 'months' in duration ? toInteger(duration.months) : 0
-  const weeks = 'weeks' in duration ? toInteger(duration.weeks) : 0
-  const days = 'days' in duration ? toInteger(duration.days) : 0
-  const hours = 'hours' in duration ? toInteger(duration.hours) : 0
-  const minutes = 'minutes' in duration ? toInteger(duration.minutes) : 0
-  const seconds = 'seconds' in duration ? toInteger(duration.seconds) : 0
+  const years = duration.years ? toInteger(duration.years) : 0
+  const months = duration.months ? toInteger(duration.months) : 0
+  const weeks = duration.weeks ? toInteger(duration.weeks) : 0
+  const days = duration.days ? toInteger(duration.days) : 0
+  const hours = duration.hours ? toInteger(duration.hours) : 0
+  const minutes = duration.minutes ? toInteger(duration.minutes) : 0
+  const seconds = duration.seconds ? toInteger(duration.seconds) : 0
 
   // Add years and months
   const date = toDate(dirtyDate)

src/add/test.ts

@@ -5,50 +5,76 @@ import assert from 'assert'
 import add from '.'
 import { getDstTransitions } from '../../test/dst/tzOffsetTransitions'
 
-describe('add', function() {
-  it('adds the values from the given object', function() {
+describe('add', function () {
+  it('adds the values from the given object', function () {
     const result = add(new Date(2014, 8 /* Sep */, 1, 10, 19, 50), {
       years: 2,
       months: 9,
       weeks: 1,
       days: 7,
       hours: 5,
       minutes: 9,
-      seconds: 30
+      seconds: 30,
     })
     assert.deepStrictEqual(result, new Date(2017, 5 /* June */, 15, 15, 29, 20))
   })
 
-  it('returns same date object when passed empty duration values', function() {
+  it('supports an undefined value in the duration object', function () {
+    const result = add(new Date(2014, 8 /* Sep */, 1, 10, 19, 50), {
+      years: undefined,
+      months: 9,
+      weeks: 1,
+      days: 7,
+      hours: 5,
+      minutes: 9,
+      seconds: 30,
+    })
+    assert.deepStrictEqual(result, new Date(2015, 5 /* June */, 15, 15, 29, 20))
+  })
+
+  it('returns same date object when passed empty duration values', function () {
+    const result = add(new Date(2014, 8 /* Sep */, 1, 10).getTime(), {
+      years: undefined,
+      months: undefined,
+      weeks: undefined,
+      days: undefined,
+      hours: undefined,
+      minutes: undefined,
+      seconds: undefined,
+    })
+    assert.deepStrictEqual(result, new Date(2014, 8 /* Sep */, 1, 10))
+  })
+
+  it('returns same date object when passed undefined duration values', function () {
     const result = add(new Date(2014, 8 /* Sep */, 1, 10).getTime(), {})
     assert.deepStrictEqual(result, new Date(2014, 8 /* Sep */, 1, 10))
   })
 
-  it('accepts a timestamp', function() {
+  it('accepts a timestamp', function () {
     const result = add(new Date(2014, 8 /* Sep */, 1, 10).getTime(), {
-      hours: 4
+      hours: 4,
     })
     assert.deepStrictEqual(result, new Date(2014, 8 /* Sep */, 1, 14))
   })
 
-  it('converts a fractional number to an integer', function() {
+  it('converts a fractional number to an integer', function () {
     const result = add(new Date(2014, 8 /* Sep */, 1, 10), { hours: 4.2 })
     assert.deepStrictEqual(result, new Date(2014, 8 /* Sep */, 1, 14))
   })
 
-  it('implicitly converts number arguments', function() {
+  it('implicitly converts number arguments', function () {
     // @ts-expect-error
     const result = add(new Date(2014, 8 /* Sep */, 1, 10), { hours: '4.2' })
     assert.deepStrictEqual(result, new Date(2014, 8 /* Sep */, 1, 14))
   })
 
-  it('does not mutate the original date', function() {
+  it('does not mutate the original date', function () {
     const date = new Date(2014, 8 /* Sep */, 1, 10)
     add(date, { hours: 4 })
     assert.deepStrictEqual(date, new Date(2014, 8 /* Sep */, 1, 10))
   })
 
-  it('works well if the desired month has fewer days and the provided date is in the last day of a month', function() {
+  it('works well if the desired month has fewer days and the provided date is in the last day of a month', function () {
     const date = new Date(2014, 11 /* Dec */, 31)
     const result = add(date, { months: 9 })
     assert.deepStrictEqual(result, new Date(2015, 8 /* Sep */, 30))
@@ -61,14 +87,14 @@ describe('add', function() {
 
   dstOnly(
     `works at DST-end boundary in local timezone: ${tz || '(unknown)'}`,
-    function() {
+    function () {
       const date = dstTransitions.end
       const result = add(date!, { hours: 1 })
       assert.deepStrictEqual(result, new Date(date!.getTime() + HOUR))
     }
   )
 
-  it('handles dates before 100 AD', function() {
+  it('handles dates before 100 AD', function () {
     const initialDate = new Date(0)
     initialDate.setFullYear(-1, 10 /* Nov */, 30)
     initialDate.setHours(0, 0, 0, 0)
@@ -79,18 +105,18 @@ describe('add', function() {
     assert.deepStrictEqual(result, expectedResult)
   })
 
-  it('returns `Invalid Date` if the given date is invalid', function() {
+  it('returns `Invalid Date` if the given date is invalid', function () {
     const result = add(new Date(NaN), { hours: 5 })
     assert(result instanceof Date && isNaN(result.getTime()))
   })
 
-  it('throws RangeError exception if passed Number as duration', function() {
+  it('throws RangeError exception if passed Number as duration', function () {
     // @ts-expect-error
     const result = add(new Date(2014, 8, 1), 'wut')
     assert(result instanceof Date && isNaN(result.getTime()))
   })
 
-  it('throws TypeError exception if passed less than 2 arguments', function() {
+  it('throws TypeError exception if passed less than 2 arguments', function () {
     // @ts-expect-error
     assert.throws(add.bind(null), TypeError)
     // @ts-expect-error

src/sub/index.js

@@ -48,13 +48,13 @@ export default function sub(dirtyDate, duration) {
 
   if (!duration || typeof duration !== 'object') return new Date(NaN)
 
-  const years = 'years' in duration ? toInteger(duration.years) : 0
-  const months = 'months' in duration ? toInteger(duration.months) : 0
-  const weeks = 'weeks' in duration ? toInteger(duration.weeks) : 0
-  const days = 'days' in duration ? toInteger(duration.days) : 0
-  const hours = 'hours' in duration ? toInteger(duration.hours) : 0
-  const minutes = 'minutes' in duration ? toInteger(duration.minutes) : 0
-  const seconds = 'seconds' in duration ? toInteger(duration.seconds) : 0
+  const years = duration.years ? toInteger(duration.years) : 0
+  const months = duration.months ? toInteger(duration.months) : 0
+  const weeks = duration.weeks ? toInteger(duration.weeks) : 0
+  const days = duration.days ? toInteger(duration.days) : 0
+  const hours = duration.hours ? toInteger(duration.hours) : 0
+  const minutes = duration.minutes ? toInteger(duration.minutes) : 0
+  const seconds = duration.seconds ? toInteger(duration.seconds) : 0
 
   // Subtract years and months
   const dateWithoutMonths = subMonths(toDate(dirtyDate), months + years * 12)

src/sub/test.js

@@ -13,19 +13,45 @@ describe('sub', () => {
       days: 7,
       hours: 5,
       minutes: 9,
-      seconds: 30
+      seconds: 30,
     })
     assert.deepEqual(result, new Date(2014, 8 /* Sep */, 1, 10, 19, 50))
   })
 
+  it('supports an undefined value in the duration object', function () {
+    const result = sub(new Date(2017, 5 /* June */, 15, 15, 29, 20), {
+      years: undefined,
+      months: 9,
+      weeks: 1,
+      days: 7,
+      hours: 5,
+      minutes: 9,
+      seconds: 30,
+    })
+    assert.deepEqual(result, new Date(2016, 8 /* Sep */, 1, 10, 19, 50))
+  })
+
+  it('returns same date object when passed empty duration values', function () {
+    const result = sub(new Date(2014, 8 /* Sep */, 1, 10).getTime(), {
+      years: undefined,
+      months: undefined,
+      weeks: undefined,
+      days: undefined,
+      hours: undefined,
+      minutes: undefined,
+      seconds: undefined,
+    })
+    assert.deepStrictEqual(result, new Date(2014, 8 /* Sep */, 1, 10))
+  })
+
   it('returns same date object when passed empty duration', () => {
     const result = sub(new Date(2014, 8 /* Sep */, 1, 10).getTime(), {})
     assert.deepEqual(result, new Date(2014, 8 /* Sep */, 1, 10))
   })
 
   it('accepts a timestamp', () => {
     const result = sub(new Date(2014, 8 /* Sep */, 1, 14).getTime(), {
-      hours: 4
+      hours: 4,
     })
     assert.deepEqual(result, new Date(2014, 8 /* Sep */, 1, 10))
   })