From 8443a233cc7fcefdf8134cebe81395648c364f3b Mon Sep 17 00:00:00 2001
From: jouae <oipc9801@gmail.com>
Date: Thu, 4 Dec 2025 20:29:33 +0800
Subject: [PATCH] Add zero-duration note handling in web app

Handle cases where note off evnents occur at the same time as note on
evnents, preventing negative duration notes from being proocessed.
---
 web/app.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/web/app.js b/web/app.js
index 2d58e2f..a2396b1 100644
--- a/web/app.js
+++ b/web/app.js
@@ -312,13 +312,13 @@ function parseMidiFile(buffer) {
             active.set(evt.note, evt.time);
         } else {
             const start = active.get(evt.note);
-            if (start !== undefined) {
+            if (start !== undefined && evt.time >= start) {
                 const duration = evt.time - start;
                 const beatVal = Math.max(1, Math.round(duration * 4 / ticksPerBeat));
                 notes.push(evt.note);
                 beats.push(beatVal);
-                active.delete(evt.note);
             }
+            active.delete(evt.note);
         }
     }