User::CheckDuplicate PHP Method

    public function CheckDuplicate()
    {
        $pass = true;
        foreach ($this->users as $user => $data) {
            if ($data['username'] == $this->username) {
                $pass = false;
            }
        }
        return $pass;
    }

 $count = ldap_count_entries($socket, $result);
 // Ensure count is definitely equal to 1
 if ($count === 1) {
     // Get the entry from the search result, and bind using its DN.
     $data = ldap_get_entries($socket, $result);
     $auth = ldap_bind($socket, $data[0]['dn'], $User->password);
     // Check the return value of the bind action.
     if ($auth === -1) {
         // Deny login and send message, An LDAP error occurred.
         die(formatJSEND("error", "An LDAP error has occurred: " . ldap_error($socket)));
     } elseif ($auth == false) {
         // Invalid login.
         die(formatJSEND("error", "Invalid user name or password."));
     } elseif ($auth == true) {
         // Check if user already exists within users.php.
         if ($User->CheckDuplicate()) {
             // Check if we can create a user within users.php.
             if ($createuser == true) {
                 // Save array back to JSON and set the session username.
                 $User->users[] = array('username' => $User->username, 'password' => null, 'project' => "");
                 saveJSON("users.php", $User->users);
                 $_SESSION['user'] = $User->username;
             } else {
                 // Deny login and send message, the user doesn't exist within users.php.
                 die(formatJSEND("error", "User " . $User->username . " does not exist within Codiad."));
             }
         } else {
             // Set the session username.
             $_SESSION['user'] = $User->username;
         }
         // Set the session language, if given, or set it to english as default.