diff --git a/src/App.tsx b/src/App.tsx
index f4d7073..78e4844 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -13,20 +13,20 @@ function App() {
   function connect() {
     WebMidi.enable()
     .then(
-        (_: WebMidi) => midiReady(),
+        (_) => midiReady(),
         (err) => console.log('Something went wrong', err));
   }
 
   function midiReady() {
     // react to device changes.
     //midi.addEventListener('statechange', (event) => initDevices(event.target));
-    initDevices(WebMidi);
+    initDevices();
   }
 
-  function initDevices(midi: WebMidi) {
+  function initDevices() {
     //console.log(midi)
     let midiOutputMap = new Map()
-    midi.outputs.forEach((outputInfo: Output) => {
+    WebMidi.outputs.forEach((outputInfo: Output) => {
       console.log(outputInfo.id)
       midiOutputMap.set(outputInfo.id, outputInfo)
     })
@@ -57,13 +57,15 @@ function App() {
     if(selectedMidiDevice) {
       let outputDevice = midiDeviceMap.get(selectedMidiDevice)
       let midiChannel = 2
-      outputDevice.sendControlChange(1, 127, {channels: midiChannel})
-      pause(50)
-      outputDevice.sendProgramChange(bankNumber, {channels: midiChannel})
-      pause(200)
-      outputDevice.sendControlChange(1, 0, {channels: midiChannel})
-      pause(50)
-      outputDevice.sendProgramChange(patchNumber, {channels: midiChannel})
+      if(outputDevice) {
+        outputDevice.sendControlChange(1, 127, {channels: midiChannel})
+        pause(50)
+        outputDevice.sendProgramChange(bankNumber, {channels: midiChannel})
+        pause(200)
+        outputDevice.sendControlChange(1, 0, {channels: midiChannel})
+        pause(50)
+        outputDevice.sendProgramChange(patchNumber, {channels: midiChannel})
+      }
     }
 
   }