Fix desync on bpm change

Author: WWRS

index.html

@@ -285,6 +285,10 @@ <h3>Examples</h3>
 
   <div class="container">
     <h2>Version history</h2>
+    <p>
+      v1.9c<br>
+      Fixed an issue where tempo changes could desync
+    </p>
     <p>
       v1.9b<br>
       Fixed an issue where tempo changes were applied at the wrong time

src/midiToNotes.js

@@ -88,8 +88,8 @@ const MidiToNotes = (function () {
       const bType = getEventType(b);
 
       // Tempo change events
-      if (aType === "meta" && a.metaType == 81) aPriority = 2;
-      if (bType === "meta" && b.metaType == 81) bPriority = 2;
+      if (aType === "meta" && a.metaType === 81) aPriority = 2;
+      if (bType === "meta" && b.metaType === 81) bPriority = 2;
 
       if (
         (aType === "noteOn" || aType === "noteOff") &&
@@ -112,6 +112,10 @@ const MidiToNotes = (function () {
       return bPriority - aPriority;
     });
 
+    for (let i = 1; i < allMidiEvents.length; i++) {
+      allMidiEvents[i].deltaTime = allMidiEvents[i].time - allMidiEvents[i-1].time;
+    }
+
     return allMidiEvents;
   }