save progress in local storage

client/src/state/localStorage.ts

@@ -0,0 +1,19 @@
+const KEY = "progress";
+export function loadState() {
+  try {
+    const serializedState = localStorage.getItem(KEY);
+    if (!serializedState) return undefined;
+    return JSON.parse(serializedState);
+  } catch (e) {
+    return undefined;
+  }
+}
+
+export async function saveState(state: any) {
+  try {
+    const serializedState = JSON.stringify(state);
+    localStorage.setItem(KEY, serializedState);
+  } catch (e) {
+    // Ignore
+  }
+}