Fix CountUp printing -0 when a value crosses or rounds to zero (#3221)

Co-authored-by: codecalm <codecalm@gmail.com>

core/js/src/countup.ts

@@ -331,14 +331,18 @@ class CountUp extends BaseComponent {
     }
 
     if (format === 'time') {
-      const minutes = Math.round(Math.abs(value))
-      return `${value < 0 ? '-' : ''}${prefix}${Math.floor(minutes / 60)}:${String(minutes % 60).padStart(2, '0')}${suffix}`
+      // Rounded away from zero on both sides, so -90.5 and 90.5 give the same
+      // minutes; a value that rounds to 0 stays unsigned (-0 < 0 is false).
+      const rounded = Math.sign(value) * Math.round(Math.abs(value))
+      const minutes = Math.abs(rounded)
+      return `${rounded < 0 ? '-' : ''}${prefix}${Math.floor(minutes / 60)}:${String(minutes % 60).padStart(2, '0')}${suffix}`
     }
 
-    const [integer, fraction] = Math.abs(value).toFixed(decimalPlaces).split('.') as [string, string | undefined]
+    const fixed = value.toFixed(decimalPlaces)
+    const [integer, fraction] = fixed.replace('-', '').split('.') as [string, string | undefined]
     const grouped = useGrouping ? integer.replace(/\B(?=(\d{3})+(?!\d))/g, separator) : integer
 
-    return `${value < 0 ? '-' : ''}${prefix}${grouped}${fraction ? decimal + fraction : ''}${suffix}`
+    return `${Number(fixed) < 0 ? '-' : ''}${prefix}${grouped}${fraction ? decimal + fraction : ''}${suffix}`
   }
 }
 

core/js/tests/unit/countup.spec.ts

@@ -239,6 +239,15 @@ describe('CountUp', () => {
       instance.reset()
       expect(element().textContent).toBe('50,000')
     })
+
+    it('should not print a negative zero when a value rounds to zero', async () => {
+      fixtureEl.innerHTML = '<h1 data-countup>-0.3</h1>'
+
+      quick({ decimalPlaces: 0 })
+      await wait(300)
+
+      expect(element().textContent).toBe('0')
+    })
   })
 
   describe('format', () => {
@@ -262,6 +271,31 @@ describe('CountUp', () => {
       expect(element().textContent).toBe('9999999999')
     })
 
+    it('should not print a negative zero when a time rounds to zero minutes', async () => {
+      fixtureEl.innerHTML = '<h1 data-countup=\'{"format":"time"}\'>0:00</h1>'
+
+      const instance = new CountUp(element(), { autoAnimate: false, duration: 0.1, format: 'time' })
+      await wait(300)
+      instance.update(-0.4)
+      await wait(300)
+
+      expect(element().textContent).toBe('0:00')
+    })
+
+    it('should round negative half minutes like positive ones in the time format', async () => {
+      fixtureEl.innerHTML = '<h1>0:00</h1>'
+
+      const instance = new CountUp(element(), { autoAnimate: false, duration: 0.1, format: 'time' })
+      await wait(300)
+      instance.update(90.5)
+      await wait(300)
+      expect(element().textContent).toBe('1:31')
+
+      instance.update(-90.5)
+      await wait(300)
+      expect(element().textContent).toBe('-1:31')
+    })
+
     it('should use a formatter function from the config', async () => {
       quick({ formatter: (value: number) => `${Math.round(value / 1000)}k` })
       await wait(300)