Dark theme for calling device selection

ts/util/theme.ts

@@ -0,0 +1,20 @@
+// Copyright 2020 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { missingCaseError } from './missingCaseError';
+
+export enum Theme {
+  Light,
+  Dark,
+}
+
+export function themeClassName(theme: Theme): string {
+  switch (theme) {
+    case Theme.Light:
+      return 'light-theme';
+    case Theme.Dark:
+      return 'dark-theme';
+    default:
+      throw missingCaseError(theme);
+  }
+}