format() not corresponding to date.

[maguirre-tribalyte]

I have the following ISO-formatted string: 2022-02-28T13:57:02.000Z

When I do console.log(dayjs(isoString).tz("Australia/Sydney")) the date object prints as follows:

M {
  '$L': 'en',
  '$d': 2022-02-28T23:57:02.000Z,
  '$x': { '$timezone': 'Australia/Sydney' },
  '$y': 2022,
  '$M': 2,
  '$D': 1,
  '$W': 2,
  '$H': 0,
  '$m': 57,
  '$s': 2,
  '$ms': 0,
  '$offset': 660,
  '$u': false
}

For my application, I need to get the date that is in the $d field, like 2022-02-28, but when I do .format("YYYY-MM-DD") it returns 2022-03-01 Expected behavior

It should return 2022-02-28

Information

• Day.js Version [e.g. v1.10.8]
• OS: [Linux]
• Browser: Node 16
• Time zone: [CET]

[BePo65]

Perhaps the documentation is not too clear (at least not the starting page for time zone).

You have to differentiate between

• 'parsing in time zone' (dayjs.tz(isoString, 'Australia/Sydney') - gives always '2022-02-28T13:57:02+11:00') and
• 'converting to time zone' (dayjs(isoString).tz('Australia/Sydney') - gives in time zone cet '2022-03-01T00:57:02+11:00' as cet = +02:00)

So just use the 'parsing' syntax and you get what you expected.