Joining data between paths based on id using AngularFire - angularjs

Question

I am currently working on an app using firebase and angularJS (ionic). Basically this is a car management app, so you have people sharing their cars with others. I tried to structure the data as flat as possible to be efficient. My issue here is that if without problem I can display the list of the car_id of the different cars shared with the logged user, I can't find a way to display the list of cars shared with the user displaying the year and the model.
Thank you in advance for your help !
{
"rules": {
"users": {
".write": true,
"$uid": {
".read": "auth != null && auth.uid == $uid"
},
"cars": {
"car_id":true,
"role":true // Owner, borower...
}
},
"cars": {
"car_id":true,
"model":true,
"year":true
}
}
}
carapp.controller("carsController", function($scope, $firebaseObject, $ionicPopup, $ionicHistory) {
$ionicHistory.clearHistory();
$scope.list = function() {
frbAuth = frb.getAuth();
if(frbAuth) {
var userObject = $firebaseObject(frb.child("users/" + frbAuth.uid));
userObject.$bindTo($scope, "user");
$scope.cars = frb.child("cars");
}}
$scope.createCar = function() {
$ionicPopup.prompt({
model: 'Create a new car',
inputType: 'text'
})
.then(function(result) {
if(result !== "") {
var newCar = $scope.cars.push({
model: result
})
var newCarId = newCar.key();
$scope.user.cars.push({car_id: newCarId, role: "owner" });
} else {
console.log("Action not completed");
}
});
}
});
<div class="list">
<a ng-repeat="car in user.cars" >
<h2>{{car.car_id}}</h2> ----> works fine !
<h2>{{car.model}}</h2> ----> How to get this working ?
<h2>{{car.year}}</h2> ----> How to get this working ?
</a>
</div>

Answer 1

In the users/ path, begin by storing the list of cars by index, instead of in an array. So your structure would be:
{
"users": {
"kato": {
"cars": {
"DeLorean": true
}
}
},
"cars": {
"DeLorean": {
model: "DeLorean",
year: "1975"
}
}
}
To join this using AngularFire, you have several approaches available. An AngularFire-only solution might look like this, taking advantage of $extend:
app.factory('CarsByUser', function($firebaseArray) {
return $firebaseArray.$extend({
$$added: function(snap) {
return new Car(snap);
},
$$updated: function(snap) {
// nothing to do here; the value of the index is not used
},
$$removed: function(snap) {
this.$getRecord(snap.key()).destroy();
},
// these could be implemented in a manner consistent with the
// use case and above code, for simplicity, they are disabled here
$add: readOnly,
$save: readOnly
});
var carsRef = new Firebase(...).child('cars');
function Car(snap) {
// create a reference to the data for a specific car
this.$id = snap.key();
this.ref = carsRef.child(this.$id);
// listen for changes to the data
this.ref.on('value', this.updated, this);
}
Car.prototype.updated = function(snap) {
this.model = data.model;
this.year = data.year;
}
Car.prototype.destroy = function() {
this.ref.off('value', this.meta, this);
};
function readOnly() { throw new Error('This is a read only list'); }
});
app.controller('...', function($scope, CarsByUser, authData) {
// authenticate first, preferably with resolve
var ref = new Firebase(...).child(authData.uid);
$scope.cars = CarsByUser($scope);
});
For a more sophisticated and elegant approach, one could utilize NormalizedCollection and pass that ref into the AngularFire array:
app.controller('...', function($scope, $firebaseArray) {
var ref = new Firebase(...);
var nc = new Firebase.util.NormalizedCollection(
ref.child('users/' + authData.uid),
ref.child('cars')
)
.select('cars.model', 'cars.year')
.ref();
$scope.cars = $firebaseArray(nc);
});