[Modal] Convert code to typescript

[leventdeniz]

• I have followed (at least) the PR section of the contributing guide.

closes #34716

[michaldudak]

Thanks for your work! There is a couple of changes needed before we can merge it.

[michaldudak]

Why the || div is added? This changes the default behavior and makes the backdrop always visible.

[leventdeniz]

useSlotProps expects elementType not to be undefined, so I added this as a default that seemed reasonable.
After checking other usages, maybe this would be better?

Suggested change

	const BackdropComponent = components?.Backdrop || 'div';
	const BackdropComponent = components?.Backdrop ?? 'div';

If not, I need some Help resolving this.

[michaldudak]

In this case, it seems it's necessary to extend useSlotProps with the support for undefined component types. It should return an empty object then. This could be done in a separate PR to keep things focused. Would you like to work on it as well?

[leventdeniz]

Yes, I would love to do that.

[michaldudak]

All right, so let's get that one done first and then we can go back to the Modal.

[leventdeniz]

Thank you for your review, I will work on these on the weekend!

[mui-bot]

	Messages
📖	Netlify deploy preview: https://deploy-preview-34793--material-ui.netlify.app/

Details of bundle changes

Generated by 🚫 dangerJS against b511f65

[leventdeniz]

I can't seem to get these last two type errors solved. Maybe someone could help me with them.

[michaldudak]

Do you need any help resolving merge conflicts or making CI checks green?

Regarding type errors, you need to cast the const ModalUnstyled to OverridableComponent<ModalUnstyledTypeMap> as React.forwardRef messes up the generics.
The proper definition of types should allow for the removal of the last @ts-expect-error in ModalUnstyled.spec.tsx.

[leventdeniz]

I did what you suggested but this somehow gave me even more errors in the ModalUnstyled.test.tsx.
Thank you for your patience but I think I need help resolving these last few errors.

[michaldudak]

You have done the majority of hard work, thanks! The remaining issue was missing types of React.createRef. I added them.
I also removed one of the tests as prop forwarding is already being tested in describeConformanceUnstyled.

[leventdeniz]

Thank you so much for your patience and help, I really appreciate it!

[michaldudak]

Thank you for contributing! Feel free to tackle any other issues.