Facebook Service (factory) to defer a call until the FB SDK instance is ready (or execute the deferred calls, or perform an immediate call, when the FB object is ready)

AngularJS-Facebook.js

(function(){
    var FBModule = angular.module('AngularFB', []);

    var _fb_has_initialized = false;

    var SDK = function($scope) {
        this.$scope = $scope;
        this._initialized = false;
        this._calls = [];
    };

    SDK.prototype._makeCall = function(toCall) {
        if (!this._initialized) {
            this._calls.push(toCall);
        } else {
            toCall();
        }
    };
    SDK.prototype.isInitialized = function() {
        return this._initialized;
    };
    SDK.prototype.initialize = function() {
        angular.forEach(this._calls, function(v) {
            v();
        }, this);
        this._initialized = true;
    };
    SDK.prototype.wrap = function(call) {
        var c = this;
        return (typeof call !== 'function') ? call : function(){
            var args = [];
            angular.forEach(arguments, function(argument) {
                args.push(c.wrap(argument));
            });
            console.log(args);
            c.$scope.$apply(function(){
                call.apply(null, args);
            });
        };
    };
    SDK.prototype.init = function(params) {
        var c = this;
        this._makeCall(function(){
            FB.init(params);
        });
    };
    SDK.prototype.api = function(path, method, params, callback) {
        var c = this;
        this._makeCall(function(){
            FB.api(
                c.wrap(path),
                c.wrap(method),
                c.wrap(params),
                c.wrap(callback)
            );
        });
    };
    SDK.prototype.ui = function(params, callback){
        var c = this;
        this._makeCall(function(){
            FB.ui(
                c.wrap(params),
                c.wrap(callback)
            );
        });
    };
    SDK.prototype.getLoginStatus = function(callback, force) {
        var c = this;
        this._makeCall(function(){
            FB.getLoginStatus(
                c.wrap(callback),
                c.wrap(force)
            );
        });
    };
    SDK.prototype.login = function(callback, options) {
        var c = this;
        this._makeCall(function(){
            FB.login(
                c.wrap(callback),
                c.wrap(options)
            );
        });
    };
    SDK.prototype.logout = function(callback) {
        var c = this;
        this._makeCall(function(){
            FB.logout(
                c.wrap(callback)
            );
        });
    };
    SDK.prototype.getAuthResponse = function(callback) {
        while (!this._initialized) {
            //noop
        }
        return FB.getAuthResponse();
    };

    SDK.prototype.custom = function() {
        var c = this;
        var parameters = [FB];
        var call = Array.prototype.shift.apply(arguments);
        angular.forEach(arguments, function(argument) {
            parameters.push(c.wrap(argument));
        });
        this._makeCall(function() {
            FB[call].apply(parameters);
        });
    };

    var _sdk = null;
    function sdk($rootScope) {
        if (_sdk == null) {
            _sdk = new SDK($rootScope);
        }
        if (_fb_has_initialized && !_sdk.isInitialized()) {
            _sdk.initialize()
        }
        return _sdk
    }

    function initialize() {
        if (_sdk && !_sdk.isInitialized()) {
            _sdk.initialize();
        }
        _fb_has_initialized = true;
    }

    FBModule.factory('AngularFB.SDK', ['$rootScope', sdk]);

    FBModule.run(['$window', function($window){
        $window.angularFBInit = initialize;
    }]);
})();