(function(window){
    'use strict';

    function define_library(){
        var Library = {};
        var name = "Timmy";

        Library.greet = function(){
            console.log("Hello from the " + name + " library.");
        }

        return Library;
    }

    //define globally if it doesn't already exist
    if(typeof(Library) === 'undefined'){
        window.Library = define_library();
    }
    else{
        console.log("Library already defined.");
    }

})(window);

// Usage
Library.greet()