index.js
function() {
      if (!volume || volume.level >= 1) {
        return;
      }

      var newVolume = Math.min(volume.level + volumeStep, 1);

      p.setVolume(newVolume, function(err, status) {
        if (err) {
          return;
        }

        debug("volume up: %s", status.level);

        volume = status;
      });
    }
function() {
      if (!volume || volume.level >= 1) {
        return;
      }

      var newVolume = Math.min(volume.level + volumeStep, 1);

      p.setVolume(newVolume, function(err, status) {
        if (err) {
          return;
        }

        debug("volume up: %s", status.level);

        volume = status;
      });
    }
volume up