1 files changed, 39 insertions, 0 deletions
diff --git a/src/frontend/app/hooks/useSessionState.ts b/src/frontend/app/hooks/useSessionState.ts
new file mode 100644
index 0000000..f5a9b4e
--- /dev/null
+++ b/src/frontend/app/hooks/useSessionState.ts
@@ -0,0 +1,39 @@
+import { useCallback, useState } from "react";
+
+/**
+ * Like useState, but backed by sessionStorage so state survives back-navigation
+ * within the same browser tab. Cleared when the tab is closed.
+ */
+export function useSessionState<T>(
+  key: string,
+  defaultValue: T
+): [T, (updater: T | ((prev: T) => T)) => void] {
+  const [state, setStateRaw] = useState<T>(() => {
+    try {
+      const stored = sessionStorage.getItem(key);
+      return stored !== null ? (JSON.parse(stored) as T) : defaultValue;
+    } catch {
+      return defaultValue;
+    }
+  });
+
+  const setState = useCallback(
+    (updater: T | ((prev: T) => T)) => {
+      setStateRaw((prev) => {
+        const next =
+          typeof updater === "function"
+            ? (updater as (prev: T) => T)(prev)
+            : updater;
+        try {
+          sessionStorage.setItem(key, JSON.stringify(next));
+        } catch {
+          // sessionStorage may be unavailable (private browsing quota, etc.)
+        }
+        return next;
+      });
+    },
+    [key]
+  );
+
+  return [state, setState];
+}