Permissions popup context iso

ts/hooks/usePrevious.ts

@@ -0,0 +1,11 @@
+// Copyright 2020-2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { useRef } from 'react';
+
+export function usePrevious<T>(initialValue: T, currentValue: T): T {
+  const previousValueRef = useRef<T>(initialValue);
+  const result = previousValueRef.current;
+  previousValueRef.current = currentValue;
+  return result;
+}