var responses = { 

        hi: "Hi there!",

        hello: "Hello,hello!",

        "good morning": "Good morning, pal!",

        "good evening": "Good evening, sir!"

    };

    var default_response = "I don't know what to say. Try to say 'hello' or 'hi'.";

​

    var input = "H.E,L:;!?L()[o]{}";

    var key = input.toLowerCase().replace(/[.,:;!?(){}\[\]]+/g, '');

    var result = key in responses ? responses[key] : default_response;

    console.log(result);