mastering-animate-presence

Mastering AnimatePresence

Review Motion code for AnimatePresence and exit animation best practices.

How It Works

1. Read the specified files (or prompt user for files/pattern)
2. Check against all rules below
3. Output findings in file:line format

Rule Categories

Priority	Category	Prefix
1	Exit Animations	exit-
2	Presence Hooks	presence-
3	Mode Selection	mode-
4	Nested Exits	nested-

Rules

Exit Animation Rules

exit-requires-wrapper

Conditional motion elements must be wrapped in AnimatePresence.

Fail:

{isVisible && (
  <motion.div exit={{ opacity: 0 }} />
)}

Pass:

<AnimatePresence>
  {isVisible && (
    <motion.div exit={{ opacity: 0 }} />
  )}
</AnimatePresence>

exit-prop-required

Elements inside AnimatePresence should have exit prop defined.

Fail:

<AnimatePresence>
  {isOpen && (
    <motion.div initial={{ opacity: 0 }} animate={{ opacity: 1 }} />
  )}
</AnimatePresence>

Pass:

<AnimatePresence>
  {isOpen && (
    <motion.div
      initial={{ opacity: 0 }}
      animate={{ opacity: 1 }}
      exit={{ opacity: 0 }}
    />
  )}
</AnimatePresence>

exit-key-required

Dynamic lists inside AnimatePresence must have unique keys.

Fail:

<AnimatePresence>
  {items.map((item, index) => (
    <motion.div key={index} exit={{ opacity: 0 }} />
  ))}
</AnimatePresence>

Pass:

<AnimatePresence>
  {items.map((item) => (
    <motion.div key={item.id} exit={{ opacity: 0 }} />
  ))}
</AnimatePresence>

exit-matches-initial

Exit animation should mirror initial for symmetry.

Fail:

<motion.div
  initial={{ opacity: 0, y: 20 }}
  animate={{ opacity: 1, y: 0 }}
  exit={{ scale: 0 }}
/>

Pass:

<motion.div
  initial={{ opacity: 0, y: 20 }}
  animate={{ opacity: 1, y: 0 }}
  exit={{ opacity: 0, y: 20 }}
/>

Presence Hook Rules

presence-hook-in-child

useIsPresent must be called from child of AnimatePresence, not parent.

Fail:

function Parent() {
  const isPresent = useIsPresent(); // Wrong location
  return (
    <AnimatePresence>
      {show && <Child />}
    </AnimatePresence>
  );
}

Pass:

function Child() {
  const isPresent = useIsPresent(); // Correct location
  return <motion.div data-exiting={!isPresent} />;
}

presence-safe-to-remove

When using usePresence, always call safeToRemove after async work.

Fail:

function AsyncComponent() {
  const [isPresent, safeToRemove] = usePresence();

  useEffect(() => {
    if (!isPresent) {
      cleanup(); // Never calls safeToRemove
    }
  }, [isPresent]);
}

Pass:

function AsyncComponent() {
  const [isPresent, safeToRemove] = usePresence();

  useEffect(() => {
    if (!isPresent) {
      cleanup().then(safeToRemove);
    }
  }, [isPresent, safeToRemove]);
}

presence-disable-interactions

Disable interactions on exiting elements using isPresent.

Fail:

function Card() {
  const isPresent = useIsPresent();
  return <button onClick={handleClick}>Click</button>;
  // Button clickable during exit
}

Pass:

function Card() {
  const isPresent = useIsPresent();
  return (
    <button onClick={handleClick} disabled={!isPresent}>
      Click
    </button>
  );
}

Mode Selection Rules

mode-wait-doubles-duration

Mode "wait" nearly doubles animation duration; adjust timing accordingly.

Fail:

<AnimatePresence mode="wait">
  <motion.div transition={{ duration: 0.3 }} />
</AnimatePresence>
// Total time: ~600ms (too slow)

Pass:

<AnimatePresence mode="wait">
  <motion.div transition={{ duration: 0.15 }} />
</AnimatePresence>
// Total time: ~300ms (acceptable)

mode-sync-layout-conflict

Mode "sync" causes layout conflicts; position exiting elements absolutely.

Fail:

<AnimatePresence mode="sync">
  {items.map(item => (
    <motion.div exit={{ opacity: 0 }}>{item}</motion.div>
  ))}
</AnimatePresence>
// Exiting and entering elements compete for space

Pass:

<AnimatePresence mode="popLayout">
  {items.map(item => (
    <motion.div exit={{ opacity: 0 }}>{item}</motion.div>
  ))}
</AnimatePresence>

mode-pop-layout-for-lists

Use popLayout mode for list reordering animations.

Fail:

<AnimatePresence>
  {items.map(item => <ListItem key={item.id} />)}
</AnimatePresence>
// Layout shifts during exit

Pass:

<AnimatePresence mode="popLayout">
  {items.map(item => <ListItem key={item.id} />)}
</AnimatePresence>

Nested Exit Rules

nested-propagate-required

Nested AnimatePresence must use propagate prop for coordinated exits.

Fail:

<AnimatePresence>
  {isOpen && (
    <motion.div exit={{ opacity: 0 }}>
      <AnimatePresence>
        {items.map(item => (
          <motion.div key={item.id} exit={{ scale: 0 }} />
        ))}
      </AnimatePresence>
    </motion.div>
  )}
</AnimatePresence>
// Children vanish instantly when parent exits

Pass:

<AnimatePresence propagate>
  {isOpen && (
    <motion.div exit={{ opacity: 0 }}>
      <AnimatePresence propagate>
        {items.map(item => (
          <motion.div key={item.id} exit={{ scale: 0 }} />
        ))}
      </AnimatePresence>
    </motion.div>
  )}
</AnimatePresence>

nested-consistent-timing

Parent and child exit durations should be coordinated.

Fail:

// Parent exits in 100ms, children in 500ms
<motion.div exit={{ opacity: 0 }} transition={{ duration: 0.1 }}>
  <motion.div exit={{ scale: 0 }} transition={{ duration: 0.5 }} />
</motion.div>

Pass:

// Parent waits for children or exits simultaneously
<motion.div exit={{ opacity: 0 }} transition={{ duration: 0.2 }}>
  <motion.div exit={{ scale: 0 }} transition={{ duration: 0.15 }} />
</motion.div>

Output Format

When reviewing files, output findings as:

file:line - [rule-id] description of issue

Example:
components/modal/index.tsx:23 - [exit-requires-wrapper] Conditional motion.div not wrapped in AnimatePresence
components/modal/index.tsx:45 - [exit-prop-required] Missing exit prop on motion element

Summary Table

After findings, output a summary:

Rule	Count	Severity
exit-requires-wrapper	2	HIGH
exit-prop-required	3	HIGH
mode-wait-doubles-duration	1	MEDIUM

References

• Motion AnimatePresence Documentation
• MDN @starting-style