Can't update a constant

static/app.js

@@ -7,7 +7,7 @@ const btn = document.getElementById("myBtn");
 
 // Get the <span> element that closes the modal
 const span = document.getElementsByClassName("close")[0];
-const mode = new URLSearchParams(window.location.search).get("mode");
+var mode = new URLSearchParams(window.location.search).get("mode");
 
 const archiveLink = document.querySelector("#archive-link")
 const pendingLink = document.querySelector("#pending-link")