dayjs core bug with locale plugin

> dayjs('4/23/22', 'M/DD/YY').locale('en').format('LT')
'12:00 AM'
> dayjs('4/23/22', 'M/DD/YY').locale('en').format('LTS')
'12:00:00 AM'
> dayjs('4/23/22', 'M/DD/YY').locale('en').format('L')
'04/23/2022'
> dayjs('4/23/22', 'M/DD/YY').locale('en').format('LL')
'April 23, 2022'
> dayjs('4/23/22', 'M/DD/YY').locale('en').format('LLL')
'April 23, 2022 12:00 AM'
> dayjs('4/23/22', 'M/DD/YY').locale('en').format('LLLL')
'Saturday, April 23, 2022 12:00 AM'
> dayjs('4/23/22', 'M/DD/YY').locale('en').format('l')
Uncaught TypeError: Cannot read properties of undefined (reading 'replace')
    at /Users/user/Projects/web/node_modules/.pnpm/[email protected]/node_modules/dayjs/plugin/localizedFormat.js:1:676
    at String.replace (<anonymous>)
    at /Users/user/Projects/web/node_modules/.pnpm/[email protected]/node_modules/dayjs/plugin/localizedFormat.js:1:563
    at r.format (/Users/user/Projects/web/node_modules/.pnpm/[email protected]/node_modules/dayjs/plugin/localizedFormat.js:1:761)
    at e.format (/Users/user/Projects/web/node_modules/.pnpm/[email protected]/node_modules/dayjs/plugin/preParsePostFormat.js:1:592)
    at u.format (/Users/user/Projects/web/node_modules/.pnpm/[email protected]/node_modules/dayjs/plugin/utc.js:1:1655)
> dayjs('4/23/22', 'M/DD/YY').locale('zh').format('l')
'2022/4/23'
> dayjs('4/23/22', 'M/DD/YY').locale('de').format('l')
'23.4.2022'

As you can see, there is an uncaught typeerror above for "l", "ll", "lll", and "llll" usage for certain locales, e.g. en.

Apr 11 '23 17:04 titanism

The reason is because the englishFormats object does not contain it.

https://github.com/iamkun/dayjs/blob/00c223b7e92970d07557133994fcb225a6d4c960/src/plugin/localizedFormat/utils.js#L5-L12

Needs to have l, ll, lll, and llll added. Will submit a PR now.

Apr 11 '23 17:04 titanism

This has been tested. Confirmed my PR works per #2282.

Please merge and release to npm with patch version bump.

Ping me back once done please! Thank you @iamkun.

> dayjs('4/23/22', 'M/DD/YY').locale('en').format('l') // this is with the PR
'4/23/2022'

Apr 11 '23 17:04 titanism

I don't agree with your conclusion, because I looked up the source code and found this

const B = b && b.toUpperCase()
return a || formats[b] || englishFormats[b] || t(formats[B])

Apr 14 '23 06:04 tendguo

@tendguo you are incorrect as that output is undefined, and you get an uncaught exception TypeError. From my tests on the latest version of dayjs it is an error when you require all the locales and then run the above commands.

Apr 14 '23 17:04 titanism

there should be no problem with localizedFormat plugin

https://runkit.com/embed/yzvddg5czfg6