diff --git a/docs/demo/index.js b/docs/demo/index.js
index a46312749..ceaa9b22f 100644
--- a/docs/demo/index.js
+++ b/docs/demo/index.js
@@ -20,3 +20,5 @@ dayjs().subtract(1, 'year').format()
 // diff
 dayjs().diff(dayjs().add(1, 'year'), 'year')
 
+// isBefore
+dayjs().isBefore(dayjs().add(1, 'year'))