From c8cf1dc712847d9802b3a527ed337a8e75303943 Mon Sep 17 00:00:00 2001
From: Chandler Abraham <cbabraham@gmail.com>
Date: Tue, 22 Jul 2025 21:49:40 -0700
Subject: [PATCH] fix(midi): ensure midin initializes device state correctly

The midin function only initialized the refs object for a device on the initial MIDI setup. This caused an error if a second MIDI device was connected in the same session, as its refs object would not exist, leading to a 'cannot read properties of undefined' error when accessed.

This commit fixes the issue by ensuring that the refs object for a given MIDI input is initialized every time  is called, not just on the first call.
---
 packages/midi/midi.mjs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/packages/midi/midi.mjs b/packages/midi/midi.mjs
index ce7cdb0e2..faa45f32d 100644
--- a/packages/midi/midi.mjs
+++ b/packages/midi/midi.mjs
@@ -493,6 +493,9 @@ export async function midin(input) {
         otherInputs?.length ? `Also available: ${getMidiDeviceNamesString(otherInputs)}` : ''
       }`,
     );
+  }
+  // ensure refs for this input are initialized
+  if (!refs[input]) {
     refs[input] = {};
   }
   const cc = (cc) => ref(() => refs[input][cc] || 0);