dont try to send midi if no midi output exists

src/midi.js

@@ -1,4 +1,8 @@
-export async function sendMidiMessage(midiChannelName, sampleNumber, midiAccess) {
+export async function sendMidiMessage(
+  midiChannelName,
+  sampleNumber,
+  midiAccess
+) {
   try {
     console.log(midiChannelName, sampleNumber);
     const availableMidiOutputs = midiAccess.outputs.values();
@@ -16,6 +20,7 @@ export async function sendMidiMessage(midiChannelName, sampleNumber, midiAccess)
       }
     }
 
+    if (!midiOut) return;
     // MIDI Note On (Play Note)
     midiOut.send([0x90, 35 + sampleNumber, 127]);
 

src/script.js

@@ -4,7 +4,6 @@ import { DataStream } from "./socket.js";
 import { Renderer } from "./render.js";
 
 document.addEventListener("DOMContentLoaded", async () => {
-
   const midiAccess = await navigator.requestMIDIAccess();
   const conductor = new Conductor();
   await conductor.init();
@@ -13,24 +12,27 @@ document.addEventListener("DOMContentLoaded", async () => {
   let strikes = 0;
   const strikeEvery = 2;
 
-
   const renderer = new Renderer();
 
   dataStream.addEventListener("strike", () => {
     console.log(strikes);
     //** select instrument */
-    if (strikes === strikeEvery){
-
+    if (strikes === strikeEvery) {
       const keys = Object.keys(instruments);
       const randomIndex = Math.floor(Math.random() * keys.length);
       const selectedInstrument = instruments[keys[randomIndex]];
-  
+
       //** select sample */
       const numSamples = selectedInstrument.numSamples;
       const randomSampleNumber = Math.floor(Math.random() * numSamples);
-  
+
       renderer.placeIcon(selectedInstrument);
-      sendMidiMessage(selectedInstrument.midiChannelName, randomSampleNumber + 1, midiAccess);
+      if (midiAccess)
+        sendMidiMessage(
+          selectedInstrument.midiChannelName,
+          randomSampleNumber + 1,
+          midiAccess
+        );
       strikes = 0;
     }
     strikes++;