Refactor setAlarm function to validate input earlier in the process

Author: Darkidd77

Sprint-3/alarmclock/alarmclock.js

@@ -9,15 +9,20 @@ function setAlarm() {
     return;
   }
 
+  let timeInSeconds = Number(inputElement.value);
+
+  if (isNaN(timeInSeconds) || timeInSeconds < 0) {
+    alert("Please enter a valid number of seconds.");
+    return;
+  }
+
   if (timerInterval) {
     clearInterval(timerInterval);
   }
   if (flashInterval) {
     clearInterval(flashInterval);
   }
 
-  let timeInSeconds = Number(inputElement.value);
-
   function updateScreen(secondsRemaining) {
     const minutes = Math.floor(secondsRemaining / 60);