Before Ember setter

before.js

handleLocationChange: function() {
 this.removeOldMarkers(this.get(‘currentLocations’));
 this.set(‘currentLocations’, this.get(‘locations’);
 this.addMarkers(this.get(‘locations’));
}.observes(‘locations’),

removeOldMarkers: function(markers) {
 markers.forEach(function(marker) {
   // remove markers from Google map
 });
}

addMarkers: function(markers) {
 markers.forEach(function(marker) {
   // add markers to Google map
 });
}