Apply badMutable plugin locally

[marnixhoh]

While this is not technically a bug, I do believe that this is a very important feature for compatibility with moment based libraries.

Current behavior
Applying a plugin (using .extend()) alters the global dayjs constructor. For dayjs to be a replacement for moment in e.g. third party libraries, it is sometimes necessary to use the badMutable plugin.

But when this plugin is applied, whether manually or by some third party code, all dayjs instances in the code base suddenly become mutable, which can lead to unexpected behavior and nasty bugs.

Expected behavior
It should be possible to apply the badMutable plugin locally, to prevent all dayjs instances to suddenly become mutable.

By looking at the source code, I couldn't find a way to make this possible.

Any help or suggestions, would be highly appreciated!!

Thanks :D

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There has been a discussion on this before: #655
And this exact issue has let react-day-picker (~4.6K ⭐) to stop using dayjs.