Apologies for not being specific enough. Was having troubles unpacking the notification payload. Found that this method works:

notificationReceived:function(notification, payload, sender) { if (notification === 'CALENDAR_EVENTS' && sender.name === 'calendar') { var x = payload; for (let value of x) {

then I was able to use variables such as x[0] or value.title/startDate/endDate etc, to access the data.