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import type {
UseHoverOptions,
UseHoverReturn,
OnHoverChangeCallback,
} from "./types";
import { isHoverSupported, normalizeDelay, createNoopRef } from "./utils";
/**
* A React hook for detecting hover state on elements.
*
* Features:
* - Efficient mouseenter/mouseleave detection
* - Configurable enter/leave delays (useful for tooltips and dropdowns)
* - Dynamic enable/disable support
* - SSR compatible with graceful degradation
* - TypeScript support with full type inference
* - Optional touch event support for hybrid devices
* - Both object and tuple destructuring support
*
* @template T - The type of HTML element the ref will be attached to
* @param options - Configuration options for the hook
* @returns Object containing ref callback and isHovered boolean (also iterable as tuple)
*
* @example
* ```tsx
* // Basic usage
* function Component() {
* const { ref, isHovered } = useHover<HTMLDivElement>();
* return (
* <div ref={ref} style={{ background: isHovered ? 'lightblue' : 'white' }}>
* {isHovered ? 'Hovering!' : 'Hover me'}
* </div>
* );
* }
* ```
*
* @example
* ```tsx
* // Tuple destructuring (alternative API)
* function Component() {
* const [ref, isHovered] = useHover<HTMLDivElement>();
* return <div ref={ref}>{isHovered ? 'Hovering!' : 'Hover me'}</div>;
* }
* ```
*
* @example
* ```tsx
* // With delay - useful for tooltips
* function Tooltip() {
* const { ref, isHovered } = useHover<HTMLButtonElement>({
* delay: { enter: 500, leave: 100 }
* });
* return (
* <button ref={ref}>
* Hover me
* {isHovered && <span className="tooltip">Tooltip content</span>}
* </button>
* );
* }
* ```
*
* @example
* ```tsx
* // With onChange callback
* function TrackedElement() {
* const { ref, isHovered } = useHover<HTMLDivElement>({
* onChange: (hovered, event) => {
* console.log('Hover state:', hovered);
* if (event) {
* console.log('Event position:', event.clientX, event.clientY);
* }
* }
* });
* return <div ref={ref}>Tracked element</div>;
* }
* ```
*
* @example
* ```tsx
* // Conditional enabling
* function ConditionalHover({ isActive }: { isActive: boolean }) {
* const { ref, isHovered } = useHover<HTMLDivElement>({
* enabled: isActive
* });
* return <div ref={ref}>{isHovered ? 'Active & Hovered' : 'Hover me'}</div>;
* }
* ```
*
* @example
* ```tsx
* // With touch support for mobile devices
* function MobileTooltip() {
* const { ref, isHovered } = useHover<HTMLButtonElement>({
* detectTouch: true,
* delay: { enter: 0, leave: 1500 }
* });
* return (
* <button ref={ref}>
* {isHovered ? 'Tapped/Hovered!' : 'Tap or hover'}
* </button>
* );
* }
* ```
*/
export function useHover<T extends Element = HTMLElement>(
options: UseHoverOptions = {}
): UseHoverReturn<T> {
const {
enabled = true,
delay = 0,
onChange,
initialHovered = false,
detectTouch = false,
} = options;
// ============ SSR Check ============
const isSupported = isHoverSupported();
// ============ Refs for internal state (no re-renders) ============
const targetRef = useRef<T | null>(null);
const enterDelayRef = useRef<ReturnType<typeof setTimeout> | null>(null);
const leaveDelayRef = useRef<ReturnType<typeof setTimeout> | null>(null);
// Store callbacks in refs to avoid effect dependencies
const onChangeRef = useRef<OnHoverChangeCallback | undefined>(onChange);
onChangeRef.current = onChange;
// Force re-render trigger for ref changes
const [, forceUpdate] = useState({});
// ============ State ============
const [isHovered, setIsHovered] = useState<boolean>(initialHovered);
// ============ Normalize delay values ============
const { enterDelay, leaveDelay } = normalizeDelay(delay);
// ============ Clear timeouts helper ============
const clearTimeouts = useCallback(() => {
if (enterDelayRef.current !== null) {
clearTimeout(enterDelayRef.current);
enterDelayRef.current = null;
}
if (leaveDelayRef.current !== null) {
clearTimeout(leaveDelayRef.current);
leaveDelayRef.current = null;
}
}, []);
// ============ Event Handlers ============
const handleMouseEnter = useCallback(
(event: MouseEvent | TouchEvent) => {
clearTimeouts();
if (enterDelay > 0) {
enterDelayRef.current = setTimeout(() => {
setIsHovered(true);
onChangeRef.current?.(true, event);
enterDelayRef.current = null;
}, enterDelay);
} else {
setIsHovered(true);
onChangeRef.current?.(true, event);
}
},
[enterDelay, clearTimeouts]
);
const handleMouseLeave = useCallback(
(event: MouseEvent | TouchEvent) => {
clearTimeouts();
if (leaveDelay > 0) {
leaveDelayRef.current = setTimeout(() => {
setIsHovered(false);
onChangeRef.current?.(false, event);
leaveDelayRef.current = null;
}, leaveDelay);
} else {
setIsHovered(false);
onChangeRef.current?.(false, event);
}
},
[leaveDelay, clearTimeouts]
);
// ============ Ref Callback ============
const setRef = useCallback((node: T | null) => {
const prevTarget = targetRef.current;
targetRef.current = node;
Eif (prevTarget !== node) {
forceUpdate({});
}
}, []);
// ============ Effect: Manage Event Listeners ============
useEffect(() => {
// SSR guard
Iif (!isSupported) {
return;
}
// Don't attach if disabled
if (!enabled) {
// Reset hover state when disabled
setIsHovered(false);
clearTimeouts();
return;
}
// Don't attach if no target
const target = targetRef.current;
if (!target) {
return;
}
// Add event listeners
target.addEventListener("mouseenter", handleMouseEnter as EventListener);
target.addEventListener("mouseleave", handleMouseLeave as EventListener);
// Optional touch events for hybrid devices
if (detectTouch) {
target.addEventListener(
"touchstart",
handleMouseEnter as EventListener,
{ passive: true }
);
target.addEventListener("touchend", handleMouseLeave as EventListener, {
passive: true,
});
}
// Cleanup
return () => {
clearTimeouts();
target.removeEventListener(
"mouseenter",
handleMouseEnter as EventListener
);
target.removeEventListener(
"mouseleave",
handleMouseLeave as EventListener
);
if (detectTouch) {
target.removeEventListener(
"touchstart",
handleMouseEnter as EventListener
);
target.removeEventListener(
"touchend",
handleMouseLeave as EventListener
);
}
};
}, [
enabled,
isSupported,
handleMouseEnter,
handleMouseLeave,
detectTouch,
clearTimeouts,
// eslint-disable-next-line react-hooks/exhaustive-deps
targetRef.current,
]);
// ============ Cleanup on unmount ============
useEffect(() => {
return () => {
clearTimeouts();
};
}, [clearTimeouts]);
// ============ SSR Return ============
Iif (!isSupported) {
const ssrResult: UseHoverReturn<T> = {
ref: createNoopRef<T>(),
isHovered: initialHovered,
[Symbol.iterator]: function* () {
yield this.ref;
yield this.isHovered;
},
};
return ssrResult;
}
// ============ Return with iterator support ============
const result: UseHoverReturn<T> = {
ref: setRef,
isHovered,
[Symbol.iterator]: function* () {
yield this.ref;
yield this.isHovered;
},
};
return result;
}
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