Once connected to a BLE device clicking on FAB will disconnect from device

static/js/BLE.js

@@ -37,8 +37,11 @@ async function disconnect() {
         "characteristicvaluechanged",
         handleNotifications
       );
+      btn.classList.remove("bg-green-600");
+      btn.classList.add("bg-blue-600");
     } catch (error) {
-      log("Argh! " + error);
+      console.log("Argh! " + error);
+      swal("Oops", error, "error");
     }
   }
 }
@@ -71,7 +74,6 @@ function parseCSC(e) {
   if (prevRes) {
     let rpm = revsToRPM(prevRes, res);
     if (rpm > 0)
-      //socket.emit("message", { rpm: parseFloat(rpm.toFixed(2)), id: 1 });
       fetch("/cadence", {
         method: "POST",
         headers: {
@@ -103,10 +105,14 @@ function revsToRPM(prevRes, res) {
   return rpm;
 }
 
-btn.addEventListener("click", () =>
+btn.addEventListener("click", () => {
+  if (!characteristic) {
     connect({
       onChange: parseCSC,
     }).catch((err) => {
       swal("Oops", err, "error");
-  })
-);
+    });
+  } else {
+    disconnect();
+  }
+});