From 6f025cddd28f7e96fb1a39a557acae2eef8cf2d6 Mon Sep 17 00:00:00 2001
From: Richard Knoll <riknoll@users.noreply.github.com>
Date: Wed, 20 Mar 2024 14:23:19 -0700
Subject: [PATCH] Fix exception when disposing sim sequencers (#9919) (#9928)

---
 pxtsim/sound/sequencer.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pxtsim/sound/sequencer.ts b/pxtsim/sound/sequencer.ts
index dd07851b072c..f96b3b432690 100644
--- a/pxtsim/sound/sequencer.ts
+++ b/pxtsim/sound/sequencer.ts
@@ -41,6 +41,7 @@ namespace pxsim.music {
 
         dispose() {
             if (this.metronome) this.metronome.dispose();
+            this.metronome = undefined
             this.stop();
             this.currentlyPlaying = undefined;
             this.listeners = {};
@@ -84,7 +85,7 @@ namespace pxsim.music {
         stop(sustainCurrentSounds = false) {
             if (this._state === "stop") return;
             this._state = "stop";
-            this.metronome.stop();
+            if (this.metronome) this.metronome.stop();
             this.fireStateChange();
 
             if (!sustainCurrentSounds) this.currentCancelToken.cancelled = true;