Move to TanStack Start from Next.js (#184)

web/app/hooks/use-is-mounted.ts

@@ -0,0 +1,19 @@
+import * as React from "react"
+
+/**
+ * Hook to check if component is still mounted
+ *
+ * @returns {boolean} true if the component is mounted, false otherwise
+ */
+export function useIsMounted() {
+  const isMounted = React.useRef(false)
+
+  React.useEffect(() => {
+    isMounted.current = true
+    return () => {
+      isMounted.current = false
+    }
+  }, [])
+
+  return React.useCallback(() => isMounted.current, [])
+}