Error TypeError: this.onready is not a function from internal browser of the facebook IOS application

Question

I integrated my project with Facebook authorization https://developers.facebook.com/docs/facebook-login/web

The Rollbar shows next error

TypeError: this.onready is not a function. (In 'this.onready(a)', 'this.onready' is undefined)

from file https://connect.facebook.net/en_US/sdk.js from the internal browser of the facebook IOS application (version 172, 171, 170).

Tell me please what the problem is and how to fix it?

$.ajaxSetup({cache: true});
window.fbAsyncInit = function() {
    if(typeof FB != 'undefined'){
        FB.init({
          appId      : fb_app_id,
          cookie     : true,
          xfbml      : true,
          version    : 'v2.8'
        });

        FB.getLoginStatus(function(response) {
            if (response.status == 'connected') {
                    onLogin(response);
                } else {
                FB.login(function(response) {
                    onLogin(response);
                }, {scope: 'user_friends, email'});
            }
        });
    }
    else{
        Rollbar.debug("Not loaded base SDK");
        return false;
    }
};

(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 = "https://connect.facebook.net/en_US/sdk.js";
    fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));

function checkLoginState() {

    if(typeof FB == 'undefined'){
        Rollbar.debug("FB is undefined. Was a problem loading the Facebook resources. Maybe your provider temporarily blocks this resource");
        return false;
    }

    FB.getLoginStatus(function(response) {
        onLogin(response);
    });
}

Answer 1

We are having the same problem.
It looks like there's a bug in Facebook's code. Inside the SDK -

                 var i = "fbNativeReady";
                 a = {
                    onready: function(a) {
                        __p && __p();
                        if (!h.nativeApp()) {
                            g.error("FB.Native.onready only works when the page is rendered in a WebView of the native Facebook app. Test if this is the case calling FB.UA.nativeApp()");
                            return
                        }
                        window.__fbNative && !this.nativeReady && ES("Object", "assign", !1, this, window.__fbNative);
                        if (this.nativeReady) a();
                        else {
                            var b = function b(c) {
                                window.removeEventListener(i, b), this.onready(a)
                            };
                            window.addEventListener(i, b, !1)
                        }
                    }
                };

You can see that the event listener "b" isn't bound, so when the event "fbNativeReady" is dispatched, the listener is invoked without a context, meaning "this" is window, and no "onready" function exists on it.
binding b to "this" can fix this issue.

A possible solution can be to run this code after a certain delay to avoid having fbNativeReady event dispatched after the code was loaded