diff --git a/src/structs.h b/src/structs.h
index 5a2d6fd..d0823bc 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -2728,3 +2728,11 @@
     void	*js_cookie;	/* can be used by js_fill */
 };
 typedef struct js_reader js_read_T;
+
+/* mode for a channel */
+typedef enum
+{
+    MODE_RAW = 0,
+    MODE_JSON,
+    MODE_JS
+} ch_mode_T;