The values ​​of dayjs().unix() and dayjs().utc().unix are the same, but dayjs().format('YYYY-MM-DD HH:mm:ss') and dayjs().utc().format('YYYY-MM-DD HH:mm:ss') are different

[XiaoXiaoWu98]

Describe the bug
The values ​​of dayjs().unix() and dayjs().utc().unix are the same, but dayjs().format('YYYY-MM-DD HH:mm:ss') and dayjs().utc().format('YYYY-MM-DD HH:mm:ss') are different

Expected behavior

The values ​​of dayjs().unix() and dayjs().utc().unix should be different

Information

• Day.js Version [e.g. v1.0.0]
• OS: [e.g. iOS]
• Browser [e.g. chrome 62]
• Time zone: [e.g. GMT-07:00 DST (Pacific Daylight Time)]

[potter-man]

Unix time should not be different. After the format you see different "numbers" but omit timezone. In fact it's actually the same date local zone and UTC.

[XiaoXiaoWu98]

Unix time should not be different. After the format you see different "numbers" but omit timezone. In fact it's actually the same date local zone and UTC.

But if I want to get the UTC timestamp, I can only do it through dayjs().utc().format('YYYY-MM-DD HH:mm:ss').unix(), not directly dayjs().utc().unix(). I think the timestamp should be consistent with the time format after format.

[potter-man]

If you need unix timestamp (seconds) you don't need to format, just call .unix() on dayjs instance

dayjs().unix()                                             // 1725008613
dayjs.utc().unix()                                         // 1725008613
dayjs('2024-08-30T00:00:00Z').unix()                       // 1724976000
dayjs.utc('2024-08-30T00:00:00Z').unix()                   // 1724976000

As I mentioned you just lose information about zone and dayjs parses string in local zone

dayjs(dayjs().format('YYYY-MM-DD HH:mm:ss')).unix()        // 1725008613
dayjs(dayjs().utc().format('YYYY-MM-DD HH:mm:ss')).unix()  // 1724997813 - Z is lost

Default format includes zone

dayjs(dayjs().format()).unix()                             // 1725008613
dayjs(dayjs().utc().format()).unix()                       // 1725008613

Or you can add Z to your custom format

dayjs(dayjs().format('YYYY-MM-DD HH:mm:ssZ')).unix()       // 1725008613
dayjs(dayjs().utc().format('YYYY-MM-DD HH:mm:ssZ')).unix() // 1725008613