core/src/ons/gesture-detector.js
function on(element, type, handler, opt, hook) {
    var types = type.split(' ');
    Utils.each(types, function(type) {
      Utils.on(element, type, handler, opt);
      hook && hook(type);
    });
  }
function on(element, type, handler, opt, hook) {
    var types = type.split(' ');
    Utils.each(types, function(type) {
      Utils.on(element, type, handler, opt);
      hook && hook(type);
    });
  }
function on ( element , type , handler , opt , hook ) { var types = type . split ( ' ' ) ; Utils . each ( types , function ( type ) { Utils . on ( element , type , handler , opt ) ; hook && hook ( type ) ; } ) ; }
simple event binder with a hook and support for multiple types
@param {HTMLElement} element
@param {String} type
@param {Function} handler
@param {Object} [opt]
@param {Function} [hook]
@param {Object} hook.type
simple event binder with a hook and support for multiple types