diff --git a/src/main.js b/src/main.js
index 0847b59..e679204 100644
--- a/src/main.js
+++ b/src/main.js
@@ -2,7 +2,7 @@ import App from './App.svelte';
 
 function mkEvent(title, start, duration, ...rest) {
   start = new Date(start)
-  let end = new Date(start)
+  const end = new Date(start)
   end.setMinutes(start.getMinutes() + duration)
   return {
     title,