The key of the currently active child.
Optionalappear?: booleanWhether to run the initial transition on first mount.
The set of children to switch between. Each child should have a stable key
(or your key will fall back to its index).
OptionalclassNames?: stringBase className(s) used by CSSTransition to apply enter/exit classes.
OptionalcsstProps?: objectAny additional props are forwarded to each CSSTransition instance.
Optionalmode?: "out-in" | "in-out"Controls sequencing when activeKey changes:
"out-in": outgoing transitions out first, incoming transitions in after exit completes."in-out": incoming transitions in first, outgoing transitions out after the incoming finishes entering
(relies on onEntered).OptionalmountOnEnter?: booleanWhether to mount the transitioning child only when it begins entering.
OptionalonEnter?: (isAppearing: boolean) => voidCalled when a child begins entering.
OptionalonEntered?: (isAppearing: boolean) => voidCalled when a child finishes entering. Used to implement "in-out" sequencing.
OptionalonExited?: (isAppearing: boolean) => voidCalled when the outgoing child finishes exiting.
OptionalonExiting?: (isAppearing: boolean) => voidCalled when a child begins exiting.
Optionaltimeout?: numberTransition timeout passed to each CSSTransition.
OptionalunmountOnExit?: booleanWhether to unmount the child after it finishes exiting.
Switches between keyed children with
CSSTransition. Ensures each child key gets its ownCSSTransitioninstance to avoid state loss.