`dayjs.tz()` is building dates with incorrect timezone for many cases #1827

LeonanCarvalho · 2022-03-11T14:20:44Z

Describe the bug
When you try to use dayjs.tz factory it isn't providing the instance properly, even using some ISO formats and Date object string outputs.

Some examples using a UTC environment :

Input	Output	Expected
`2022-03-11T14:29:26.319Z`	2022-03-11T14:29:26-03:00	2022-03-11T11:29:26-03:00
`Fri, 11 Mar 2022 14:29:26 GMT`	2022-03-11T14:29:26-03:00	2022-03-11T11:29:26-03:00
`3/11/2022, 2:29:26 PM`	2022-03-11T14:29:26-03:00	2022-03-11T11:29:26-03:00
`2014-02-03T16:50:21Z`	2014-02-03T16:50:21-03:00	2014-02-03T13:50:21-03:00
`2012-02-01T13:50:21.01-03:00`	2012-02-01T16:50:21-03:00	2012-02-01T13:50:21-03:00
`2022-02-03T13:50:21-00:00`	2022-02-03T13:50:21-03:00	2022-02-03T10:50:21-03:00

The behavior is odd, for the Date input it fails sometimes but also should be accepted especially the ISO format native Date outputs.

Reproducible code:

https://gist.github.com/LeonanCarvalho/35d1596dcfb701255d04b93d70df69a0

Expected behavior
Construct dayjs with correct timezone.

Information

Day.js Version v1.10.8
OS: [e.g. iOS]
Browser: nodeJS v14.17.3
Time zone: UTC (tests in UTC but also in GMT -3)

The text was updated successfully, but these errors were encountered:

hbj · 2022-03-28T07:44:47Z

I was about to file a bug regarding dayjs.tz and found this one which seems related. The issue is that the function is not converting correctly between timezones. Simplest case to see is when converting to the same timezone is leading to the time to be changed!

Example:

dayjs.tz('2022-02-21 22:00', 'YYYY-MM-DD HH:mm', 'Europe/Paris').toISOString()
=> '2022-02-21T21:00:00.000Z'
dayjs.tz('2022-02-21 22:00', 'YYYY-MM-DD HH:mm', 'Europe/Paris').tz('Europe/Paris').toISOString()
=> '2022-02-21T22:00:00.000Z'

It seems to be applying the offset of the target timezone without taking into consideration the timezone of the original date!

h-h-h-h · 2022-03-30T11:20:26Z

Let me contribute my tests:

console.log(
  [
    // ✔️ "2022-10-30T02:00:00+02:00"
    dayjs.utc("2022-10-30 00:00").tz("Europe/Berlin"),

    // ❌ "2022-10-30T02:00:00Z"
    // ➡️ "2022-10-30T02:00:00+01:00" would be correct (duplicate local hour because of DST).
    dayjs.utc("2022-10-30 01:00").tz("Europe/Berlin"),
    dayjs.utc("2022-10-30 00:00").add(1, "h").tz("Europe/Berlin"),

    // ✔️ "2022-10-30T03:00:00+01:00"
    dayjs.utc("2022-10-30 02:00").tz("Europe/Berlin"),
    dayjs.utc("2022-10-30 00:00").add(2, "h").tz("Europe/Berlin"),

    // With add()/subtract() on IANA object, you never get out of the wrong timezone.
    // ❌ "2022-11-03T05:00:00+02:00" (add())
    // ❌ "2022-10-26T04:00:00+01:00" (subtract())
    dayjs.utc("2022-10-30 00:00").tz("Europe/Berlin").add(100, "h"),
    dayjs.utc("2022-10-30 06:00").tz("Europe/Berlin").subtract(100, "h"),

    // BTW: When add(), subtract() etc. are patched, this should return "2022-03-27T03:00:00+02:00" (missing local hour because of DST).
    dayjs.tz("2022-03-27 01:00", "Europe/Berlin").add(1, "h"),
  ].map((d) => d.format())
);

This also touches #1816.

ilyakamens · 2022-04-21T11:37:29Z

Indeed, it looks like the time changes every time a timezone conversion occurs:

I'm on Day.js 1.10.7 (and currently in Paris).

sevrai · 2022-04-26T15:22:55Z

It seems to be related to the extra offset created by Summer Time.

The switch to summer time occurred March 27th at 2AM in Paris and I got these results on an instance based in Paris:

console.log(dayjs("2022-03-27T20:00:00.000Z").tz("Europe/Paris").toISOString())
> 2022-03-27T20:00:00.000Z
console.log(dayjs("2022-03-25T20:00:00.000Z").tz("Europe/Paris").toISOString())
> 2022-03-25T21:00:00.000Z

It looks like the lib is using the current offset of the instance timezone (UTC+2 at the execution time) instead of the real one at this date.

rush86999 · 2022-06-06T20:39:03Z

I am adding my bug here as well instead of creating a new one.

Same nodejs environment: nodejs14.x
AWS lambda environment - serverless framework
"dayjs": "^1.11.0",

use the same exact date and calling timezone with true as second parameter adjusts the time to utc offset
example:

dayjs.tz.setDefault('America/Toronto')

const date = dayjs('2022-06-12T17:00:00-04:00').tz('America/Toronto', true).format()

console.log(date, ' date')
// date = 2022-06-12T17:00:00-04:00
const date2 = dayjs(date).tz('America/Toronto', true).format()

console.log(date2, ' date2')
// date2 = 2022-06-12T21:00:00-04:00

As you can see utc offset is applied if timezone is called twice. This is a bug and likely related to new nodejs environemnt possibly?

not sure at this point.

den-by · 2022-08-12T15:30:26Z

dayjs.tz('2022-02-21 22:00', 'YYYY-MM-DD HH:mm', 'Europe/Paris').toISOString()
=> '2022-02-21T21:00:00.000Z'
dayjs.tz('2022-02-21 22:00', 'YYYY-MM-DD HH:mm', 'Europe/Paris').tz('Europe/Paris').toISOString()
=> '2022-02-21T22:00:00.000Z'

To date, I get the same result 2022-02-21T21:00:00.000Z in both cases
dayjs: 1.11.5
macOS
NodeJS: 16.13.1

sevrai · 2022-08-22T08:39:14Z

To date, I get the same result 2022-02-21T21:00:00.000Z in both cases dayjs: 1.11.5 macOS NodeJS: 16.13.1

I've got the same.

In my case, release 1.11.2 solved my problem.

ilyakamens · 2022-08-22T13:16:06Z

I commented above here, and the behavior I described above is also fixed in 1.11.2.

hbj · 2022-08-25T07:57:36Z

My case seems also to be fixed. I tested it on the Day.js website in the console, so I don't know exactly in which version this has been fixed.

tonyneel · 2022-11-17T05:02:53Z

dayjs(2022-11-19).tz('America/Los_angeles') => "2022-11-18T16:00:00.000Z"

On my local it is correct. What can I do? Do I just need to use moment? I love this library but I am not sure if there is a workaround or not for timezones not working. I have had other issues with timezone as well but found workarounds.

dayjs: 1.11.5
Supabase server not suer what OS
NodeJS: 16.13.1

tonyneel · 2022-11-17T05:18:23Z

dayjs('2022-11-19 15:45:55 UTC').tz('America/Los_angeles')

This fixed it for me and Idk why. Something to look into.

dcdavidheisnam · 2023-02-14T13:31:52Z

On version 1.11.7, specifying timezone has no effect. I'm only getting the local time.

ItayTur · 2023-03-16T13:39:20Z

This is a sandbox that reproduces the timezone not affecting the date:
https://codesandbox.io/s/dayjs-business-time-forked-b7opew

pencilcheck · 2023-04-23T19:42:00Z

Related to this??
https://stackoverflow.com/questions/75129234/day-js-timezone-plugin-method-produce-an-invalid-date

pencilcheck · 2023-04-23T23:50:15Z

Recommend this over dayjs if you want to handle timezone: https://www.npmjs.com/package/date-fns-tz

throrin19 · 2023-11-10T15:49:21Z

@pencilcheck date-fns-tz is a really pain :/

anospoldigot · 2024-01-10T02:07:44Z

dayjs().tz('Asia/Jakarta').format();

use format(), this is working for me

Joeljt · 2024-01-18T09:44:39Z

It seems that dayjs can not handle the timezone with the format of Etc/GMT+8, you can get a barely correct result using this timezone format, but a correct result using the format Asia/Shanghai.

Here is my test case:

const originalDate = dayjs('2024-01-18T12:34:56');

// GMT-8 is actually GMT+8, 2024-01-18 12:34:56
console.log(originalDate.utc().tz('Etc/GMT-8').format('YYYY-MM-DD HH:mm:ss'));

// UTC standard time, correct
console.log(originalDate.utc().tz('Etc/GMT+0').format('YYYY-MM-DD HH:mm:ss')); 

// 2024-01-17 20:34:56, I have no idea what is going on here
console.log(originalDate.utc().tz('Etc/GMT+8').format('YYYY-MM-DD HH:mm:ss'));

Joeljt · 2024-01-18T12:23:54Z

It seems that dayjs can not handle the timezone with the format of Etc/GMT+8, you can get a barely correct result using this timezone format, but a correct result using the format Asia/Shanghai.

Here is my test case:
const originalDate = dayjs('2024-01-18T12:34:56');

// GMT-8 is actually GMT+8, 2024-01-18 12:34:56
console.log(originalDate.utc().tz('Etc/GMT-8').format('YYYY-MM-DD HH:mm:ss'));

// UTC standard time, correct
console.log(originalDate.utc().tz('Etc/GMT+0').format('YYYY-MM-DD HH:mm:ss')); 

// 2024-01-17 20:34:56, I have no idea what is going on here
console.log(originalDate.utc().tz('Etc/GMT+8').format('YYYY-MM-DD HH:mm:ss'));

It turns out that the Etc/ prefix would make the meaning of the whole timezone to be completely opposite than the original meaning.

For example, the Etc/GMT-8 is identical to GMT+8, and Etc/GMT+2 is the same as GMT-2 alone.

So the problem is not with dayjs, but my misunderstanding of the IANA timezone standard, although it's a little counter intuitive.

Leaving a message here in case of people may run into the same problem like me.

LeonanCarvalho closed this as completed Mar 11, 2022

LeonanCarvalho reopened this Mar 11, 2022

LeonanCarvalho changed the title ~~dayjs.tz() is not building dates with correct timezone in many cases~~ dayjs.tz() is not building dates with correct timezone for many cases May 2, 2022

LeonanCarvalho changed the title ~~dayjs.tz() is not building dates with correct timezone for many cases~~ dayjs.tz() is building dates with incorrect timezone for many cases Jan 16, 2024

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`dayjs.tz()` is building dates with incorrect timezone for many cases #1827

`dayjs.tz()` is building dates with incorrect timezone for many cases #1827

LeonanCarvalho commented Mar 11, 2022 •

edited

hbj commented Mar 28, 2022

h-h-h-h commented Mar 30, 2022

ilyakamens commented Apr 21, 2022 •

edited

sevrai commented Apr 26, 2022

rush86999 commented Jun 6, 2022 •

edited

den-by commented Aug 12, 2022 •

edited

sevrai commented Aug 22, 2022

ilyakamens commented Aug 22, 2022

hbj commented Aug 25, 2022

tonyneel commented Nov 17, 2022

tonyneel commented Nov 17, 2022

dcdavidheisnam commented Feb 14, 2023

ItayTur commented Mar 16, 2023

pencilcheck commented Apr 23, 2023

pencilcheck commented Apr 23, 2023

throrin19 commented Nov 10, 2023

anospoldigot commented Jan 10, 2024

Joeljt commented Jan 18, 2024 •

edited

Joeljt commented Jan 18, 2024 •

edited

dayjs.tz() is building dates with incorrect timezone for many cases #1827

dayjs.tz() is building dates with incorrect timezone for many cases #1827

Comments

LeonanCarvalho commented Mar 11, 2022 • edited

hbj commented Mar 28, 2022

h-h-h-h commented Mar 30, 2022

ilyakamens commented Apr 21, 2022 • edited

sevrai commented Apr 26, 2022

rush86999 commented Jun 6, 2022 • edited

den-by commented Aug 12, 2022 • edited

sevrai commented Aug 22, 2022

ilyakamens commented Aug 22, 2022

hbj commented Aug 25, 2022

tonyneel commented Nov 17, 2022

tonyneel commented Nov 17, 2022

dcdavidheisnam commented Feb 14, 2023

ItayTur commented Mar 16, 2023

pencilcheck commented Apr 23, 2023

pencilcheck commented Apr 23, 2023

throrin19 commented Nov 10, 2023

anospoldigot commented Jan 10, 2024

Joeljt commented Jan 18, 2024 • edited

Joeljt commented Jan 18, 2024 • edited

`dayjs.tz()` is building dates with incorrect timezone for many cases #1827

`dayjs.tz()` is building dates with incorrect timezone for many cases #1827

LeonanCarvalho commented Mar 11, 2022 •

edited

ilyakamens commented Apr 21, 2022 •

edited

rush86999 commented Jun 6, 2022 •

edited

den-by commented Aug 12, 2022 •

edited

Joeljt commented Jan 18, 2024 •

edited

Joeljt commented Jan 18, 2024 •

edited