Hover

Headless Hover; covers React Aria useHover, Pointer Events hover.


Package	`@vizejs/ui/hover`
Maturity	stable
Own the source	`vize lib pull hover`
Requires	—
Aliases	hover, pointer, pen
Covers	React Aria useHover, Pointer Events hover

API

`createHover`

Create an SSR-safe mouse and pen hover normalizer for one host.

function createHover(options: HoverOptions = {}): HoverController

`useHover`

Create a hover normalizer disposed with the current Vue effect scope.

function useHover(options: HoverOptions = {}): HoverController

Behavior

Normative state × input → outcome table for @vizejs/ui/hover. Every row is exercised by src/families/interaction/hover/hover*.test.ts; compile-only assertions live in src/families/interaction/hover/hover.types.test-d.ts.

#	State	Input	Outcome	Proven by
H1	idle	mouse or pen pointer enters	immutable start snapshot and hovered state are published	boundary test
H2	idle	touch or extensible unknown pointer enters	input is ignored	filter test
H3	idle	disabled or nonmatching configured family enters	input is ignored	filter test
H4	hovered	pointer moves between host descendants	hover remains owned by the host	boundary test
H5	hovered	owning pointer leaves host	normal end snapshot is emitted	boundary test
H6	hovered	reactive disabled/filter changes then pointer moves	canceled end is emitted	reactive test
H7	hovered	touch device switch, pointer cancel, blur, or hidden document	canceled end is emitted	cancellation tests
H8	touch just ended	compatibility mouse enter within 800 ms	emulated hover is ignored	legacy fallback test
H9	legacy browser	genuine mouse enter after suppression window	fallback hover starts and ends normally	legacy fallback test
H10	Pointer Events browser	compatibility mouse handlers also run	duplicate mouse lifecycle is ignored	legacy fallback test
H11	active callback re-enters	start callback cancels	stale `hovered=true` change is not published	reentrancy test
H12	callbacks throw	multiple transition notifications	state settles and failures aggregate afterward	callback-failure test
H13	active	manual cancel, dispose, or scope stop	state/listeners release with explicit cancellation semantics	ownership test
H14	concurrent SSR requests	identical component trees	byte-identical markup contains no handlers or DOM reads	SSR test
H15	SSR followed by hydration	mouse enter/leave	host identity remains and state renders without diagnostics	hydration test
H16	public TypeScript API	mutation or invalid closed union	compilation rejects misuse	`src/families/interaction/hover/hover.types.test-d.ts`

Accessibility obligation

Hover must never be the only way to discover or invoke an action. Consumers must provide equivalent focus, press, long-press, or visible-control behavior. This primitive deliberately ignores touch and unknown pointers, emits no CSS, does not change focus, and leaves semantic roles and styling entirely to the owning component.