First note priority

Hi everybody!

I've seen a bunch of scripts creating a last note priority, but I'm trying to make one that does the opposite, Play the first note you played, and not let any other note through until that first note is released.

I modified one of the last note priority scripts I found, and it kinda works. But fast notes are sometimes ignored and sometimes it let's a new note through while another is still playing. Can someone help me make this more solid?

Here is what I have now:

var hold = [];

function HandleMIDI(e) {
 var a = e instanceof NoteOn && e.velocity !=0;
 var b = e instanceof NoteOff;
 var c = e instanceof NoteOn && e.velocity ==0;

 if (a) {

   switch (hold.length) {

     case 0:
       hold.push(e.pitch);
       e.send(), e.trace();
       break;

     case 1:
       if (hold[0] != e.pitch) {
         hold.pop();
         hold.push(e.pitch);
         break;
       }
    }
 }
 
 if (b || c) {
   
   if (e.pitch != hold[0]) {
   		e.send(), e.trace();
   		hold.pop();
   }
 }
 

 if (!a && !b && !c) {
   e.send(), e.trace();
 }

}

Try this instead:

var gate = -1;

function HandleMIDI(event) {

   // if first note, close gate until Noteoff
   if(event instanceof NoteOn) {
       if (gate < 0) {
           gate = event.pitch;
           event.send();
           return;
       }
       else {
           return;  // ignore until gate open again
       }
   }
   
   // if its the right note off, open the gate again
   if(event instanceof NoteOff) {
       if (event.pitch == gate) {
           event.send();
           gate = -1;
           return;
       }
       else {
           return;  // ignore until gate open again
       }
   }
   
   // all other event types, pass through
   event.send();
}