function deepClone(val) {
    if (!isObject(val)) {
        return val;
    }

    if (val instanceof Array) {
        return val.map(deepClone);
    }

    var clone = {};
    var prop;

    for (prop in val) {
        clone[prop] = deepClone(val[prop]);
    }

    return clone;
}

function assert(condition) {
    if (!condition) {
        throw new Error('Assertion failed');
    }
}

function isObject(val) {
    return typeof val === 'object' && val !== null;
}

function deepEquals(val1, val2) {
    if (val1 instanceof Array) {
        if (!(val2 instanceof Array) || val1.length !== val2.length) {
            return false;
        }

        return val1.every(function (val1Item, index) {
            return deepEquals(val1Item, val2[index]);
        });
    }

    if (!isObject(val1) || !isObject(val2)) {
        return val1 === val2;
    }

    var val1Keys = Object.keys(val1);

    if (val1Keys.length !== Object.keys(val2).length) {
        return false;
    }

    return val1Keys.every(function (val1Key) {
        return val2.hasOwnProperty(val1Key) && deepEquals(val1[val1Key], val2[val1Key]);
    });
}

var data = {
    name: 'Paddy',
    address: {
        town: 'Lerum',
        country: 'Sweden'
    }
};

var clone = deepClone(data);

assert(deepEquals(data, clone));

clone.address.street = 'Test street';

assert(!deepEquals(data, clone));