clear timeout on error too

main.js

@@ -124,7 +124,9 @@ worker.addEventListener("message", (message) => {
 });
 worker.addEventListener("error", (e) => {
 	console.log(e);
+	clearTimeout(timeoutId);
 	document.querySelector("#result").value = e.message;
+	switchButtons(true);
 });
 
 document.querySelector("#expr").addEventListener("focus", setupExprInput);