edge case with milliseconds

fturmel · fturmel · commit 337155f7979c · 2022-07-26T07:30:57.000-04:00
diff --git a/src/roundToNearestMinutes/index.ts b/src/roundToNearestMinutes/index.ts
@@ -62,8 +62,9 @@ export default function roundToNearestMinutes<DateType extends Date>(
   }
 
   const date = toDate(dirtyDate)
-  const seconds = date.getSeconds() // relevant if nearestTo is 1, which is the default case
-  const minutes = date.getMinutes() + seconds / 60
+  const fractionalSeconds = date.getSeconds() / 60
+  const fractionalMilliseconds = date.getMilliseconds() / 1000 / 60
+  const minutes = date.getMinutes() + fractionalSeconds + fractionalMilliseconds
 
   // Unlike the `differenceIn*` functions, the default rounding behavior is `round` and not 'trunc'
   const method = options?.roundingMethod ?? 'round'
diff --git a/src/roundToNearestMinutes/test.ts b/src/roundToNearestMinutes/test.ts
@@ -3,9 +3,13 @@
 import assert from 'assert'
 import roundToNearestMinutes, { RoundToNearestMinutesOptions } from './index'
 
-function makeDate(minutes: number, seconds: number = 0) {
+function makeDate(
+  minutes: number,
+  seconds: number = 0,
+  milliseconds: number = 0
+) {
   // helper to make tests more readable since we mostly care about minutes and seconds
-  return new Date(2014, 6 /* Jul */, 10, 12, minutes, seconds, 0)
+  return new Date(2014, 6 /* Jul */, 10, 12, minutes, seconds, milliseconds)
 }
 
 describe('roundToNearestMinutes', () => {
@@ -51,13 +55,6 @@ describe('roundToNearestMinutes', () => {
     )
   })
 
-  it('rounds up to the next day', () => {
-    assert.deepStrictEqual(
-      roundToNearestMinutes(new Date(2014, 6, 10, 23, 59, 59)),
-      new Date(2014, 6, 11)
-    )
-  })
-
   describe('roundingMethod', () => {
     it('trunc, nearestTo === 1 (default)', () => {
       const options: RoundToNearestMinutesOptions = { roundingMethod: 'trunc' }
@@ -248,6 +245,27 @@ describe('roundToNearestMinutes', () => {
     })
   })
 
+  describe('edge cases', () => {
+    it('rounds up to the next day', () => {
+      assert.deepStrictEqual(
+        roundToNearestMinutes(new Date(2014, 6, 10, 23, 59, 59)),
+        new Date(2014, 6, 11)
+      )
+    })
+
+    it('ceils correctly with 0 seconds and 1 millisecond', () => {
+      assert.deepStrictEqual(
+        roundToNearestMinutes(makeDate(15, 0, 0), { roundingMethod: 'ceil' }),
+        makeDate(15)
+      )
+
+      assert.deepStrictEqual(
+        roundToNearestMinutes(makeDate(15, 0, 1), { roundingMethod: 'ceil' }),
+        makeDate(16)
+      )
+    })
+  })
+
   describe('examples', () => {
     it('example 1', () => {
       const result = roundToNearestMinutes(new Date(2014, 6, 10, 12, 12, 34))
