Incorrect date parsing in Firefox browser

[ppiyush13]

Describe the bug
Parsing date using dayJs and then converting to native JavaScript Date is not working as expected in Firefox browser.

const parsedDate = dayJs(
  "25-MAY-2021 12:00 +08:00",
  "DD-MMM-YYYY HH:mm Z"
).toDate().toString();

Output
Getting below output in Firefox browser

Fri May 25 -2021 09:53:28 GMT+0553 (India Standard Time) 

Expected output
In chrome and NodeJs, getting correct below output

Tue May 25 2021 09:30:00 GMT+0530 (India Standard Time)

Issues:

• Time is incorrect (09:53:28 instead of 09:30:00)
• Time zone is incorrect (GMT+0553 instead of GMT+0530)
• Year is negative (-2021 instead of 2021)
• Weekday is incorrect (Friday instead of Tuesday)

Could this be related to Firefox bug Inconsistent date object - Negative year in result ?

Information

• Day.js Version: 1.10.5
• OS: windows 10
• Browser: Firefox 89.0.1 (64-bit)
• Time zone: GMT+05:30 IST (India Standard Time)

Issue reproduce
I have created minimal repo to reproduce above issues https://codesandbox.io/s/determined-mayer-fsc4e?file=/src/index.js

Anyone aware of possible workarounds ?

[MirzaLeka]

I've noticed the same issue with Moment on Firefox. Scary

import * as moment from 'moment'

moment(
    "25-MAY-2021 12:00"
  ).format("YYYY-MM-dddd HH:mm:ss")

// chrome: "2021-05-Tuesday 12:00:00"
// firefox: "-2021-05-Friday 12:00:00"

Anyway, there is a workaround with the customParseFormat plugin:

import * as customParseFormat from 'dayjs/plugin/customParseFormat'
import * as dayjs from 'dayjs'

dayjs.extend(customParseFormat)
const date = dayjs('2021-05-25 12:00 PM', 'YYYY-MM-DD HH:mm A').toDate().toString()

// "Tue May 25 2021 12:00:00 GMT+0200 (Central European Summer Time)"

and the output is the same across browsers. More on that here.
Cheers!

[iamkun]

For consistent results parsing anything other than ISO 8601 strings, you should use String + Format.

ref https://day.js.org/docs/en/parse/string