diff --git a/operator-map.go b/operator-map.go
index 91b6a7b..7f38cd7 100644
--- a/operator-map.go
+++ b/operator-map.go
@@ -58,7 +58,9 @@ func evalMap(ctx kern.ExprContext, opTerm *term) (v any, err error) {
 	if err == io.EOF {
 		err = nil
 	}
-	v = values
+	if err == nil {
+		v = values
+	}
 	return
 }