diff --git a/docs/guide/output.md b/docs/guide/output.md
index 84a80cc27..151067494 100644
--- a/docs/guide/output.md
+++ b/docs/guide/output.md
@@ -100,7 +100,7 @@ const editor = new Editor({
   content: `<p>Example Content</p>`,
 
   // triggered on every change
-  onUpdate() {
+  onUpdate: () => {
     const json = this.getJSON()
     // send the content to an API here
   },