How to allow role based login in Laravel 5.4?

Using the function below I was able to add active flag, so that only those users who are active can login.

Now I have another flag called role and I wish to allow only those users with role 1 or 2 to login.

public function credentials(Request $request)
    {
        return [
            'email' => $request->email,
            'password' => $request->password,
            'active' => 1,
        ];
    }

via Chebli Mohamed