Marfeel can reconcile logged-in users using different devices. If you want a user to be reconciled across all their used devices send its user ID:
window.marfeel.cmd.push(['compass', function(compass) {
compass.setSiteUserId(1);
}]);
Replace 1 with the specific user ID you use in the format of your choice.
The provided UserId will be the one used internally on the Single Customer View
If you need to retrieve marfeel user id for forwarding it to one of our apis, the method you need to use is getUserId()
window.marfeel.cmd.push(['compass', function(compass) {
compass.getUserId(1);
}]);