diff --git a/ui/src/constants.js b/ui/src/constants.js
index 6e4dc4d44f..1829269959 100644
--- a/ui/src/constants.js
+++ b/ui/src/constants.js
@@ -1,3 +1,4 @@
+//@flow
 export const REFRESH_TIMEOUT = 15000;
 export const REFRESH_METRCIS_GRAPH = 60000;
 export const FR_LANG = 'FR';