Keyboard Trigger Conditions

Does SoundFlow support something like event.codes and listening to keyip or keydown values?

On javascript.info I came across something similar to what I'm looking for, I think. This is the script:

sf.addEventListener('keydown', function(event) {
  if (event.code == 'KeyZ' && (event.ctrlKey || event.metaKey)) {
    alert('Undo!')
  }
});

I seem to get an error with the addEventListener portion of the script but if I remove it I get errors at the "event" portions.

Technically looking for a way a script can listen to the key input from the trigger so that when I press the key it does one thing and when the ket is released it does another.