auto-claude: subtask-1-3 - Create useIntersectionObserver hook for element vi

src/hooks/useIntersectionObserver.ts

@@ -0,0 +1,45 @@
+import { useState, useEffect, useRef, RefObject } from 'react';
+
+interface UseIntersectionObserverOptions {
+  threshold?: number | number[];
+  root?: Element | null;
+  rootMargin?: string;
+}
+
+/**
+ * Hook to detect when an element is visible in the viewport using IntersectionObserver
+ * @param options - IntersectionObserver options (threshold, root, rootMargin)
+ * @returns Object containing ref to attach to element and isIntersecting state
+ */
+export const useIntersectionObserver = <T extends HTMLElement = HTMLDivElement>(
+  options: UseIntersectionObserverOptions = {}
+): { ref: RefObject<T>; isIntersecting: boolean } => {
+  const { threshold = 0.5, root = null, rootMargin = '0px' } = options;
+  const [isIntersecting, setIsIntersecting] = useState<boolean>(false);
+  const ref = useRef<T>(null);
+
+  useEffect(() => {
+    const observer = new IntersectionObserver(
+      ([entry]) => {
+        setIsIntersecting(entry.isIntersecting);
+      },
+      {
+        threshold,
+        root,
+        rootMargin,
+      }
+    );
+
+    if (ref.current) {
+      observer.observe(ref.current);
+    }
+
+    return () => {
+      if (ref.current) {
+        observer.unobserve(ref.current);
+      }
+    };
+  }, [threshold, root, rootMargin]);
+
+  return { ref, isIntersecting };
+};