header.js

xtag.register('bb-header', {
    lifecycle: {
      created: function() { Helpers.created.call(this, 'header'); }
    },
    accessors: {
        'nav': {
            attribute: {}
        },
        'navId': {
            // the attribute: {} declaration here auto-links
            // the nav-id attribute to the navId setter (this.navId).
            // Setting one sets the other, any get/set functionality
            // is called both directions.
            attribute: { name: 'nav-id' }
        },
        'navAction': {
            attribute: { name: 'nav-id' }
        },
        'heading': {
            attribute: {}
        },
        'counter': {
            attribute: {}
            set: function(){
               // do something when you use the setter bbElement.counter = ___
               this.__count__++; // Just an example
            }
        },
        'theme': {
            attribute: {}
        }
    }
});