Unix timestamp is incorrect?

[jsumners]

if (new Date().getTimezoneOffset() === 0) then dayjs.unix(1550251173).startOf('day').unix() returns 1550188800.

if (new Date().getTimezoneOffset() === 300) then dayjs.unix(1550251173).startOf('day').unix() returns 1550206800.

A Unix timestamp is by definition a count of seconds from "00:00:00 Thursday, 1 January 1970, Coordinated Universal Time (UTC)" (http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_16). Thus, the correct result should always be 1550188800.

[ghost]

Because in dayjs.unix(1550251173), dayjs parses and displays in local time. The same in momentjs.

[jsumners]

Yes, that should parse into local time. But the final conversion back to a Unix timestamp should generate a number at UTC.

[ghost]

Yes, and that will be of course different. Cause startOf('day') is different.

[jsumners]

What do you not understand? The number that results from dayjsInstance.unix() should be the number of seconds from 00:00:00 Thursday, 1 January 1970 at the UTC timezone.

[jsumners]

I'm closing this until I can figure out where the actual bug lies. I'm not really sure what is happening here.

[iamkun]

try UTC plugin

[iamkun]

🎉 This issue has been resolved in version 1.8.9 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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