Plugins: how extend only one instance of dayjs?

[gpbl]

I'm evaluating this library for react-day-picker and I have a concern about plugins.

For what I understand, extending dayjs with plugins will affect all the instances of dayjs.

E.g. if I extend dayjs with weekOfYear plugin, the dayjs instances used by an application implementing react-day-picker+dayjs will be extended too. Is it correct? If yes, how to extend just one instance of dayjs?

[iamkun]

Yes, and I can’t see if there is a problem. What’s your concern, please?

[gpbl]

Thanks @iamkun for your answer,

I don't agree much with this design choice. Not that I expect it giving practical problems for now, but an external component using dayjs would alter how dayjs works in the whole app. This doesn't sound correct to me. What I would have preferred is a factory like:

const dayjs = dayjs.factory();
dayjs.extend(aPlugin); // only this instance of dayjs will use `aPlugin`

Just my feedback! Thanks for your work on dayjs!

[iamkun]

Thanks. To keep only one type of dayjs might be better I think. 😊

[iamkun]

I'll close this issue since it's been a while since it's been opened. Feel free to reopen if you have updates on this

[szympajka]

@iamkun, I found this issue as I was actually looking for the sort of factory function.

The problem I have is this:

dayjs.extend(updateLocale);

dayjs.updateLocale('en', {
  relativeTime: {
    future: 'in %s',
    past: '%s ago',
    s: '<1 min',
    m: '1 min',
    mm: '%d mins',
    h: '1 hour',
    hh: '%d hours',
  },
});

So I updated locales according to our product needs, but now it will update it for the entire app which I believe is not what we want.

What can be a work around here?

[iamkun]

@szympajka there's no dayjs factory function atm.

In your case, it's better to use two locales.

e.g.

import somelocale from 'dayjs/locale/somelocale'

// update somelocale to other config and name
const otherlocale = {
  name: 'otherlocale',
   ...somelocale
}

// then register otherlocale
dayjs().locale(otherlocale)

// then you will have two locale config that you want

dayjs().locale(somelocale)
dayjs().locale(otherlocale)

[szympajka]

thanks, @iamkun, it helped :)

[kb-ally]

I need to have badMutable plugin in specific places not globally , any suggestions @iamkun

[marnixhoh]

@kb-ally I have the same issue. How did you end up solving it?

[gjc9620]

How to change local to UTC time?
like

dayjs().locale(UTC)?

[Nantris]

This should really be re-opened. This is the same sort of unexpected behavior that people are leaving moment to get away from.

It doesn't need to be fixed per se, but closing without resolution? Why?

[adguy360]

Hi @iamkun,

In a micro frontend architecture with a single appshell hosting multiple (full app) remotes, each remote should be able to set its own default day js configs (locale, tz ec) without affecting/overriding other remotes.
This is a common scenario with a relatively simple MF architecture, how does day js support such cases with a global singleton?

[Ecksters]

Seems like you could keep the current behavior as the default, but offer a method that returns a new untouched DayJS instance, for cases like this.

[Nantris]

@iamkun would you be open to reconsidering your previous stance? I think many developers would prefer to use dayjs instead of moment but this remains a blocker for us, and surely for others.

[rubennaatje]

For me it's an issue when using it as a replacement for moment.js in a 3rd party library.

In the rest of my codebase i do want to use the non BadMutable version of Dayjs.

[switz]

yeah would prefer plugins/updateLocale to return an immutable instance of dayjs rather than overriding global config

[beefchimi]

@iamkun the code you shared with @szympajka does not appear to work... I am unable to have a custom locale for just one component. Example here: https://codesandbox.io/s/dayjs-testing-rr26qy

That being said, I am in agreeance with other commenters in this thread - it would be ideal to spawn a unique instance of dayjs so that we can extend it without affecting any other instance.

[Nantris]

I think this package is unmaintained, but still, friendly bump.