Question

I am using the following functions:

function loop_perms(permissions) {
.... call check_perm here....
}
function check_perm(perm) {
        var result;
        FB.api(
         {
            method: 'users.hasAppPermission',
            ext_perm: perm
         }, function(response) {
            result = response;
         });
         return result;
    }

Now, the issue is that I am getting an undefined from the result of check_perm whereas in the Firebug console, I can see that response has a value of 0 or 1 (depending on perm)

Anyone knows what I am doing wrong? I am guessing it has something to do with the fact that i am trying to capture the value of a variable inside a callback.

Regards
Nikhil Gupta.

Answer 1

I assume the Facebook API is asynchronous. So at the time return result is executed, the callback was not called yet. You have to provide a callback from the calling function:

function check_perm(perm, callback) {
    var result;
    FB.api(
     {
        method: 'users.hasAppPermission',
        ext_perm: perm
     }, callback);
}

and

function loop_perms(permissions) {
    check_perm(whatever here, function(result) {
        // do something with result
    });
}