var defaults = {
    number: 1,
    bool: true,
    magic: 'real',
    animal: 'whale',
    croutons: 'delicious'
};

var options = {
    number: 2,
    magic: 'real',
    animal: 'porpoise',
    bool: false,
    random: 42
};

var settings = extend(defaults, options);

console.log(settings);
// Returns: Object{animal: "porpoise", bool: false, croutons: "delicious", magic: "real", number: 2, random: 42}