1 files changed, 9 insertions, 0 deletions
diff --git a/src/ui.sh b/src/ui.sh
index f6e225c..ea4071e 100644
--- a/src/ui.sh
+++ b/src/ui.sh
@@ -22,6 +22,15 @@ init_ui()
 	local ui="${1}"
 	local fn=
 
+	case "${ui}" in
+		'cli' | 'tui')
+			;;
+		*)
+			printf 'Error: Invalid UI "%s"\n' "${ui}" >&2
+			return 1
+			;;
+	esac
+
 	for fn in ${ui_functions}; do
 		eval "${fn}() { ${ui}_${fn} \"\${@}\"; }"
 	done