fix(plugin): timezone plugin prevent RangeError for invalid Day.js values (#3180) (#3181)

Add early-return guards in proto.tz and d.tz so that invalid dates
return an invalid Day.js instance instead of throwing when
Intl.DateTimeFormat.formatToParts receives an invalid Date.

Regression introduced in 1.11.22 by e27ee80.

Author: iamkun

src/plugin/timezone/index.js

@@ -93,6 +93,7 @@ export default (o, c, d) => {
   const proto = c.prototype
 
   proto.tz = function (timezone = defaultTimezone, keepLocalTime) {
+    if (!this.isValid()) return this
     const oldOffset = this.utcOffset()
     const date = this.toDate()
     const target = date.toLocaleString('en-US', { timeZone: timezone })
@@ -140,6 +141,11 @@ export default (o, c, d) => {
       return d(input).tz(timezone)
     }
     const localTs = d.utc(input, parseFormat).valueOf()
+    if (Number.isNaN(localTs)) {
+      const ins = d(NaN)
+      ins.$x.$timezone = timezone
+      return ins
+    }
     const [targetTs, targetOffset] = fixOffset(localTs, previousOffset, timezone)
     const ins = d(targetTs).utcOffset(targetOffset)
     ins.$x.$timezone = timezone

test/plugin/timezone.test.js

@@ -569,3 +569,15 @@ describe('DST edge cases vs moment', () => {
     })
   })
 })
+
+it('does not throw for invalid Day.js values (regression #111.22)', () => {
+  const invalid = dayjs('invalid')
+  expect(invalid.isValid()).toBe(false)
+  expect(() => invalid.tz('Europe/Skopje')).not.toThrow()
+  expect(invalid.tz('Europe/Skopje').isValid()).toBe(false)
+})
+
+it('does not throw for invalid string in d.tz()', () => {
+  expect(() => dayjs.tz('invalid', 'Europe/Skopje')).not.toThrow()
+  expect(dayjs.tz('invalid', 'Europe/Skopje').isValid()).toBe(false)
+})