grommet.TrackingObservers = grommet.TrackingObservers || []; grommet.TrackingObservers.push(['namogoo', function(type, data){ if(data.hasOwnProperty('Nb') ? data.Nb : null) { grommet.GoogleTagManager.TrackEvent({ nB: data.Nb, trackEvent: { 'category':'Namogoo', 'action':'block', 'label':'block', 'value':1 } }); } }]);