How to get the beacons in range in native ibeacon

Hello I’m using ionic native ibeacon 's starter template in here
.I want to list the beacons in range (proximity,uuid etc…) ,I tried like this ,but cant get the list of the beacons.
Which event is the best way to check if a beacon is in range when a user clicks a button in ionic app?
data =>{
console.log("didStartMonitoringForRegion: ", data)
for (let beacon of data.beacons) { //nothing
console.log(“beacon uuid :” + beacon.uuid); //nothing
error => console.error()
By the way didstartMonitoringForregion console log shows this