feat: custom loading phrase when interactive shell requires input (#12535)

packages/cli/src/ui/hooks/useInactivityTimer.ts

@@ -0,0 +1,39 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { useState, useEffect } from 'react';
+
+/**
+ * Returns true after a specified delay of inactivity.
+ * Inactivity is defined as 'trigger' not changing for 'delayMs' milliseconds.
+ *
+ * @param isActive Whether the timer should be running.
+ * @param trigger Any value that, when changed, resets the inactivity timer.
+ * @param delayMs The delay in milliseconds before considering the state inactive.
+ */
+export const useInactivityTimer = (
+  isActive: boolean,
+  trigger: unknown,
+  delayMs: number = 5000,
+): boolean => {
+  const [isInactive, setIsInactive] = useState(false);
+
+  useEffect(() => {
+    if (!isActive) {
+      setIsInactive(false);
+      return;
+    }
+
+    setIsInactive(false);
+    const timer = setTimeout(() => {
+      setIsInactive(true);
+    }, delayMs);
+
+    return () => clearTimeout(timer);
+  }, [isActive, trigger, delayMs]);
+
+  return isInactive;
+};