json printer BUGFIX missing union print
diff --git a/src/printer_json.c b/src/printer_json.c
index f67d31f..aaab210 100644
--- a/src/printer_json.c
+++ b/src/printer_json.c
@@ -351,6 +351,7 @@
     case LY_TYPE_UINT64:
     case LY_TYPE_DEC64:
     case LY_TYPE_IDENT:
+    case LY_TYPE_UNION:
         json_print_string(ctx->out, value);
         break;