refactor(core): modernize toggleFullScreen and synchronize state updates

[KristjanESPERANTO]

The method now uses async/await instead of Promise chains (.then()), making the control flow more linear and easier to follow.

Additionally, the execution order was improved: the fullscreen transition now completes before updating map._isFullscreen and firing events. This ensures that event listeners always receive the correct, up-to-date state.

A nice side effect of this change is that the code in _toggleState now reads more intuitively:

this.link.title = isFullscreen ? titleCancel : title;

Previously, the logic was inverted because the state hadn't been updated yet when the event fired.

Summary of changes:

• Refactor: Convert toggleFullScreen to async/await for better readability.
• Refactor: Centralize element and mode detection to reduce code duplication.
• Refactor: Simplify _handleFullscreenChange detection for external exits (ESC key).
• Improve: Synchronize state updates with fullscreen transition completion.
• Adjust: Update _toggleState logic to align with the new execution order.

Note on _handleFullscreenChange

The new execution order required adjusting this method: since map._exitFired is now set before exit() (not after), the condition needed to also check map._isFullscreen to correctly detect external exits (ESC key).

---

This is a polish PR - there are no functional changes, but the code should now be easier to understand and maintain.

[brunob]

As usual, thx for the detailed PR :)

[KristjanESPERANTO]

I hope it's not annoying that I'm creating so many PRs! But I think it's worth it.

[brunob]

I certainly won't blame people that give of their free time and provide help and such relevant contributions ! You can't imagine how i'm happy to see collaboration emerge on this project :)

[brunob]

Any thought @BePo65 ?

[brunob]

Thx again, if it's ok for you let's wait January to push a new release (?)

[KristjanESPERANTO]

If it's okay, a last release for this year would be nice, as the type definitions would then be included 🙂

[BePo65]

Even for me all these changes look very good.

[brunob]

If it's okay, a last release for this year would be nice, as the type definitions would then be included 🙂

I will be unavailable next two weeks, so that's why i prefer to release after this break in way to be present if anything is broken with latest changes (but i'm sure it will be ok :))

[KristjanESPERANTO]

Makes sense, no problem. Have a nice time! 🙂

[mickaeltr]

Hello @KristjanESPERANTO,
I was having a look at this and since you gently added the Typescript definitions, I am thinking they should be updated accordingly (e.g. returning Promise<void> instead of void for function signatures that changed)
Thank you

[KristjanESPERANTO]

@mickaeltr Thanks for the hint. I will have a look in the next days 🙂

[brunob]

@KristjanESPERANTO should we release a new version now, or wait a bit until you have time to take care of @mickaeltr hints ? (no hurry)

[KristjanESPERANTO]

Release would be good 👍 I handled his hints via the last PR (#245) in commit 4b83cb5 🙂

[brunob]

Et voilà, version 5.2.0 is published :)

[KristjanESPERANTO]

Nice! And I've created a PR to remove the types for leaflet.fullscreen from DefinitelyTyped: DefinitelyTyped/DefinitelyTyped#74316 🙂

Since the types are now here in the repo, they are superfluous there.