Firebase 3 way data binding not working as expected

问题

I have an AngularJS service that returns a firebase ref.

.factory('sessionManager', ['$firebase','$scope', function($firebase){
    var ref=new Firebase('https://telechat.firebaseio.com/sessions');
    return $firebase(ref);
  }])

In the controller, I have added the dependency and called $bind.

$scope.items=sessionManager;
$scope.items.$bind($scope,'sessions').then(function(unbind){
      unbind();
    });

But when I print it to the console, the returned data has a collection of functions like $add , $set ,.. etc in addition to the array of data.

Why is this occurring? Am I doing it the wrong way?

回答1:

If I'm reading the question correctly, you may be under the impression that $bind() is a transformation of the $firebase object into a raw data array or object. In essence, the only difference between a $firebase instance and $bind is that data is local changes are automagically pushed back to Firebase from Angular. Whereas, when you use $firebase without $bind, you need to call $save to push local changes.

Keeping in mind that $firebase is a wrapper on the Firebase API and not a simple data array, you can still treat it like raw data in most cases.

To iterate data in a Firebase object, you can use ngRepeat:

<li ng-repeat="(key, item) in $sessions">{{item|json}}</li>

Or if you want to apply filters that depend on arrays:

<li ng-repeat="(key, item) in $sessions | orderByPriority | filter:searchText">

Or in a controller using $getIndex:

angular.forEach($scope.sessions.$getIndex(), function(key) {
    console.log(key, $scope.sessions[key]);
});

The $add/$update/etc methods mentoined are part of the $firebase object's API. The documentation and the tutorial should be great primers for understanding this process.

This is also a part of the API that is continuing to evolve to better match the Angular way of doing things and feedback from users.

来源：https://stackoverflow.com/questions/22267077/firebase-3-way-data-binding-not-working-as-expected