demo/www/lib/ionic/js/ionic.bundle.js
function isVertical(direction) {
      return (direction == ionic.Gestures.DIRECTION_UP || direction == ionic.Gestures.DIRECTION_DOWN);
    }
function isVertical(direction) {
      return (direction == ionic.Gestures.DIRECTION_UP || direction == ionic.Gestures.DIRECTION_DOWN);
    }
function isVertical ( direction ) { return ( direction == ionic . Gestures . DIRECTION_UP || direction == ionic . Gestures . DIRECTION_DOWN ) ; }
boolean if the direction is vertical
@param    {String}    direction
@returns  {Boolean}   is_vertical
boolean if the direction is vertical