1. Used alone in response to being told by someone that they have done something or got possession of something that you wish you did or had. English = 'Lucky you!', 'What luck!', 'Can you believe it?', 'How did that happen?', 'How lucky is that?'
2. Used alone to show strong agreement with what your addressee has just said or done. English = 'That's it!', 'You are so right!', 'Spot on!' and so on.
3. Used alone to show strong support or admiration for what someone has achieved. English = 'Good on you/him/her/them etc.!', 'Good for you/him/her/them etc.' and so on.