Todos Solution

app.js

// your code goes here
var Todos = function() {
    var self = {};
    var tasks = [];

    var openedTasks = function() {
        return tasks.filter( function(t) {return t.isOpen();});
    };

    self.addTask = function(task) {
        tasks.push( task );
    };

    self.get = function(idx) {
        var opened = openedTasks();
        return opened[idx];
    };

    self.count = function() {
        var opened = openedTasks();
        return opened.length;
    };

    return self;
};

var Task = function(text) {
    var self = {};
    var open = true;

    self.done = function() {
        open = false;
    };

    self.isOpen = function() {
        return open;
    };

    self.toString = function() {
        return text;
    };

    return self;
};

var tasks = new Todos();

var t1 = new Task('Feed the dog');
var t2 = new Task('Clean up the house');
var t3 = new Task('Write JavaScript');

tasks.addTask(t1);
tasks.addTask(t2);
tasks.addTask(t3);

// print: I need to do 3 things
console.log('I need to do ' + tasks.count() + ' things');

t1.done();
t2.done();

// print: I need to do 1 thing
console.log('I need to do ' + tasks.count() + ' things');

// print: My task is: Write JavaScript
console.log('My task is: ' + tasks.get(0));

music.js

(function() {

    // Insert Code Here
    var MusicBox = function() {
        var self = {};
        var albums = [];

        self.addAlbum = function( a ) {
            albums.push( a );
        };

        self.favoriteAlbum = function() {
            return albums.reduce(function(a, b) {
                return a.countPlays() > b.countPlays() ? a : b;
            });
        };


        return self;

    };

    var Album = function(artist, title) {
        var self = {};
        var count = 0;

        self.play = function() {
            console.log("Playing " + self);
            count += 1;
        };

        self.toString = function() {
            return artist + " - " + title;
        };

        self.countPlays = function() {
            return count;
        };

        return self;
    };

    var box = new MusicBox(),
        a1 = new Album("The Who", "Tommy"),
        a2 = new Album("Tom Waits", "Closing Time"),
        a3 = new Album("John Cale", "Paris 1919"),
        favorite;

    box.addAlbum(a1);
    box.addAlbum(a2);
    box.addAlbum(a3);

    a1.play() ; // prints "Playing The Who - Tommy"
    a2.play(); // prints "Playing John Cale - Paris 1919"
    a1.play(); // prints "Playing The Who - Tommy"

    favorite = box.favoriteAlbum();

    // prints "favorite album is The Who - Tommy"
    console.log("favorite album is " + favorite);

}());