Add ability to lock the modal state

[simpson]

In some cases it would be preferable to lock the state of the modal to reduce the risk of a user losing data (Ex. form in modal). Can you add a prop that allows you to disable close when clicking anywhere in the overlay, perhaps even disabled the keyboard (esc) shortcut?

[Harrald]

An onBeforeClose event would be useful in which you could do your own checks and then stop the closing.

[mohammadzolfali5]

That's perfect.

[simpson]

Why not just add a prop for this?