How to Set with Priority in Angularfire - angularfire

Question

I'm having trouble understanding how to set with $priority in angularfire. I am trying to add a username with the key as username.
For example if I try:
var object = {user : "name",
$priority : "this"};
var ref = new Firebase(FIREBASE_URL + 'users');
var newBar = $firebase(ref);
newBar.$set(username, object);
The firebase set fails because of the invalid character "$" in priority.
I understand that instead I could try :
var object = {user : "name",
$priority : "this"};
var ref = new Firebase(FIREBASE_URL + 'users');
var newBar = $firebase(ref).$asArray();
newBar.$add(object);
This succeeds in adding the object to the array, but doesn't give me the opportunity to set the key to username as I require.
I can't think of any other way to achieve this currently. Is there any way to use set that allows me to set $priority? Or any alternative method to achieve the same?
Thanks

Answer 1

$priority is a property that exists on synchronized objects and records inside a synchronized array. As you've noted, it's not an allowed key in firebase data, so using it with $firebase::$set doesn't make sense here (since $set takes a valid json object which is stored directly into Firebase). Reading the API specifications can be a big help here.
There is also no need to create a synchronized binding for this use case. Just use the existing Firebase reference:
var ref = new Firebase(URL);
ref.child(username).set(object, function(error){ /* ... */ });
If there is some use case for working within a synchronized binding, then just use the Firebase meta property .priority:
var object = {user: "name", ".priority": "this"};
var ref = new Firebase(URL);
var sync = $firebase(ref);
sync.$set(object).then(/* ... */);

Answer 2

In case anyone else is looking at this, I have now taken the approach of using set first and then setting priority thereafter like this:
var object = {user : "name",
$priority : "this"};
var username = "user1";
var ref = new Firebase(FIREBASE_URL + 'users');
var newBar = $firebase(ref);
newBar.$set(username, object).then(function(){
var ref2 = new Firebase(FIREBASE_URL + 'users/' + username);
var newBar2 = $firebase(ref2).$asObject();
newBar2.$loaded().then(function(){
newBar2.$priority = authUser.uid;
newBar2.$save();
});
});