A simple facebook api wrapper I've been using for a couple of projects

simple_facebook_api_wrapper.js

/**
 * This is called when the response is positive (for example when the status is 'connected').
 * @callback successCallback
 */

/**
 * This is called when the response is negative (for example when the status is not 'connected').
 * @callback failureCallback
 */

/**
 * Generic callback function.
 * @callback callback
 */

function FacebookApp(){

    /**
     * @see {@link https://developers.facebook.com/apps}
     */
    this.appId = '';

    /**
     * @see {@link https://developers.facebook.com/docs/facebook-login/permissions/v2.2}
     */
    this.scope = 'public_profile,email';

    /**
     * @see {@link https://developers.facebook.com/docs/games/requests/v2.2}
     */
    this.inviteTitle = '';
    this.inviteMessage = '';
    this.inviteMaxRecipients = 5;

    /**
     * @see {@link https://developers.facebook.com/docs/javascript/reference/FB.init/v2.2}
     */
    this.initApp = function(){
        FB.init({
            appId      : this.appId,
            xfbml      : true,
            version    : 'v2.2'
        });
    };

    /**
     * @param {successCallback} isLoggedInCallback
     * @param {failureCallback} notLoggedInCallback
     * @see {@link https://developers.facebook.com/docs/reference/javascript/FB.getLoginStatus}
     */
    this.isLoggedIntoApp = function(isLoggedInCallback, notLoggedInCallback){
        FB.getLoginStatus(function(response) {
            if(response.status === 'connected'){
                isLoggedInCallback(response);
            }
            else{
                notLoggedInCallback();
            }
        });
    };

    /**
     * @param {successCallback} loginAcceptedCallback
     * @param {failureCallback} loginRejectedCallback
     * @see {@link https://developers.facebook.com/docs/reference/javascript/FB.login/v2.2}
     */
    this.login = function(loginAcceptedCallback, loginRejectedCallback){
        FB.login(function(response){
            if(response.status === 'connected'){
                loginAcceptedCallback(response);
            }
            else{
                loginRejectedCallback(response);
            }
        },{scope: this.scope});
    };

    /**
     * @param {callback} callback
     * @see {@link https://developers.facebook.com/docs/javascript/reference/FB.api}
     * @see {@link https://developers.facebook.com/docs/graph-api/reference/v2.2/user}
     */
    this.getUserInfo = function(callback){
        FB.api('/me', function(response) {
            callback(response);
        });
    };

    /**
     * @param {callback} callback
     * @see {@link https://developers.facebook.com/docs/javascript/reference/FB.ui}
     * @see {@link https://developers.facebook.com/docs/games/requests/v2.2}
     */
    this.inviteFriends = function(callback){
        FB.ui({
                method: 'apprequests',
                filters: ['app_non_users'],
                title: this.inviteTitle,
                message: this.inviteMessage,
                max_recipients: this.inviteMaxRecipients
            },
            function(response){
                callback();
            });
    };

    /**
     * @param {callback} callback
     * @see {@link https://developers.facebook.com/docs/reference/javascript/FB.Event.subscribe/v2.3}
     */
    this.addAfterPluginRenderCallback = function(callback){
        FB.Event.subscribe("xfbml.render", callback);
    };

    /**
     * @param {Object} parameters
     * @param {successCallback} successCallback
     * @param {failureCallback} failureCallback
     * @see {@link https://developers.facebook.com/docs/sharing/reference/feed-dialog/v2.3}
     */
    this.showFeedDialog = function(parameters, successCallback, failureCallback){
        parameters.method = 'feed';
        FB.ui(parameters, function(response) {
            if(response && response.post_id){
                successCallback();
            }
            else{
                failureCallback();
            }
        });
    };

    /**
     * @param {string} photoUrl
     * @param {successCallback} successCallback
     * @param {failureCallback} failureCallback
     * @see {@link https://developers.facebook.com/docs/graph-api/reference/user/photos/}
     */
    this.uploadPhoto = function(photoUrl, successCallback, failureCallback){
        FB.api(
            "/me/photos",
            "POST",
            {
                "url": photoUrl
            },
            function (response) {
                if (response && !response.error) {
                    successCallback();
                }
                else{
                    failureCallback();
                }
            }
        );
    };

}