Help with Facebook API Integration error

Help & Support
1

Hi, I’m trying to integrate Facebook API for Facebook login and Facebook leaderboard into my game using the Faceboom API tutorial available in Playcanvas Tutorial segment. While following through the tutorial I have encountered a problem while trying to add the “facebook-setup.js” to the root of the project as a script component. The error is “Uncaught error: Uncaught TypeError: cannot read property ‘on’ of null”. Project Link. Someone please help me…

(function () {
    var _fb = false;
    var _pc = false;
    var _inst = null;
    var app = null;
    
    window.fbAsyncInit = function() {
        FB.init({
            appId      : '277723253076089',
            xfbml      : true,
            version    : 'v2.5'
        });

        _fb = true;

        if (_fb && app) {
            app.fire("fb:init");
        }    
    };
   
    app = pc.Application.getApplication(); // I think this is not initializing the 'app' variable, thus I'm getting null error.
    app.on("initialize", function () {
        if (_fb) {
            app.fire("fb:init");
        }        
    });

    (function(d, s, id){
        var js, fjs = d.getElementsByTagName(s)[0];
        if (d.getElementById(id)) {return;}
        js = d.createElement(s); js.id = id;
        js.src = "//connect.facebook.net/en_US/sdk.js";
        fjs.parentNode.insertBefore(js, fjs);
    }(document, 'script', 'facebook-jssdk'));  
}());