Animation

A guide to animating Base UI components.

Base UI components can be animated using CSS transitions, CSS animations, or JavaScript animation libraries. Each component provides a number of data attributes to target its states, as well as a few attributes specifically for animation.

CSS transitions

Use the following Base UI attributes for creating transitions when a component becomes visible or hidden:

[data-starting-style] corresponds to the initial style to transition from.
[data-ending-style] corresponds to the final style to transition to.

Transitions are recommended over CSS animations, because a transition can be smoothly cancelled midway. For example, if the user closes a popup before it finishes opening, with CSS transitions it will smoothly animate to its closed state without any abrupt changes.

popover.css

.Popup {
  box-sizing: border-box;
  padding: 1rem 1.5rem;
  background-color: canvas;
  transform-origin: var(--transform-origin);
  transition:
    transform 150ms,
    opacity 150ms;

  &[data-starting-style],
  &[data-ending-style] {
    opacity: 0;
    transform: scale(0.9);
  }
}

CSS animations

Use the following Base UI attributes for creating CSS animations when a component becomes visible or hidden:

[data-open] corresponds to the style applied when a component becomes visible.
[data-closed] corresponds to the style applied before a component becomes hidden.

popover.css

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes scaleOut {
  from {
    opacity: 1;
    transform: scale(1);
  }
  to {
    opacity: 0;
    transform: scale(0.9);
  }
}

.Popup[data-open] {
  animation: scaleIn 250ms ease-out;
}

.Popup[data-closed] {
  animation: scaleOut 250ms ease-in;
}

JavaScript animations

JavaScript animation libraries such as Motion require control of the mounting and unmounting lifecycle of components in order for exit animations to play.

Base UI relies on element.getAnimations() to detect if animations have finished on an element. When using Motion, opacity animations are reflected in element.getAnimations(), so Base UI automatically waits for the animation finish before unmounting the component. If opacity isn’t part of your animation (such as in a translating drawer component), you should still animate it using a value close to 1 (such as opacity: 0.9999), so that Base UI can detect the animation.

Animating components unmounted from DOM when closed with Motion

Most popup components like Popover, Dialog, Tooltip, and Menu are unmounted from the DOM when they are closed by default. To animate them with Motion:

Make the component controlled with the open prop so <AnimatePresence> can see the state as a child
Specify keepMounted on the <Portal> part
Use the render prop to compose the <Popup> with motion.div

animated-popover.tsx

function App() {
  const [open, setOpen] = React.useState(false);

  return (
    <Popover.Root open={open} onOpenChange={setOpen}>
      <Popover.Trigger>Trigger</Popover.Trigger>
      <AnimatePresence>
        {open && (
          <Popover.Portal keepMounted>
            <Popover.Positioner>
              <Popover.Popup
                render={
                  <motion.div
                    initial={{ opacity: 0, scale: 0.8 }}
                    animate={{ opacity: 1, scale: 1 }}
                    exit={{ opacity: 0, scale: 0.8 }}
                  />
                }
              >
                Popup
              </Popover.Popup>
            </Popover.Positioner>
          </Popover.Portal>
        )}
      </AnimatePresence>
    </Popover.Root>
  );
}

Animating components kept in DOM when closed with Motion

Components that specify keepMounted remain rendered in the DOM when they are closed. These elements need a different approach to be animated with Motion:

Use the render prop to compose the <Popup> with motion.div
Animate the properties based on the open state, avoiding <AnimatePresence>

animated-popover.tsx

function App() {
  return (
    <Popover.Root>
      <Popover.Trigger>Trigger</Popover.Trigger>
      <Popover.Portal keepMounted>
        <Popover.Positioner>
          <Popover.Popup
            render={(props, state) => (
              <motion.div
                {...(props as HTMLMotionProps<'div'>)}
                initial={false}
                animate={{
                  opacity: state.open ? 1 : 0,
                  scale: state.open ? 1 : 0.8,
                }}
              />
            )}
          >
            Popup
          </Popover.Popup>
        </Popover.Positioner>
      </Popover.Portal>
    </Popover.Root>
  );
}

Animating Select component with Motion

The Select component is initially unmounted but remains mounted after interaction. To animate it with Motion, a mix of the two previous approaches is needed.

Manual unmounting

For full control, you can manually unmount the component when it’s closed once animations have finished using an actionsRef passed to the <Root>:

manual-unmount.tsx

function App() {
  const [open, setOpen] = React.useState(false);
  const actionsRef = React.useRef({ unmount: () => {} });

  return (
    <Popover.Root open={open} onOpenChange={setOpen} actionsRef={actionsRef}>
      <Popover.Trigger>Trigger</Popover.Trigger>
      <AnimatePresence>
        {open && (
          <Popover.Portal keepMounted>
            <Popover.Positioner>
              <Popover.Popup
                render={
                  <motion.div
                    initial={{ scale: 0 }}
                    animate={{ scale: 1 }}
                    exit={{ scale: 0 }}
                    onAnimationComplete={() => {
                      if (!open) {
                        actionsRef.current.unmount();
                      }
                    }}
                  />
                }
              >
                Popup
              </Popover.Popup>
            </Popover.Positioner>
          </Popover.Portal>
        )}
      </AnimatePresence>
    </Popover.Root>
  );
}