laravel login username or email

In LoginController, Overide method username.

#Documentation
in input('login'); , change key with key name in your login form.

    public function username()
    {
        $login = request()->input('login');
        $fieldType = filter_var($login, FILTER_VALIDATE_EMAIL) ? 'email' : 'username';

        request()->merge([$fieldType => $login]);

        return $fieldType;
    }