The "Transitioning elements on DOM addition and removal" example in that article uses a setTimeout() to wait an extra 1000 milliseconds before removing the element from the DOM. If you immediately remove the element from the DOM (like would usually happen if you do {isOpen && <Modal />} in React), it'll vanish immediately and won't have time to play the transition.
Comments
Even when using view transitions?
https://developer.mozilla.org/en-US/docs/Web/CSS/@starting-s...
The "Transitioning elements on DOM addition and removal" example in that article uses a setTimeout() to wait an extra 1000 milliseconds before removing the element from the DOM. If you immediately remove the element from the DOM (like would usually happen if you do {isOpen && <Modal />} in React), it'll vanish immediately and won't have time to play the transition.