Time structure

time.js

var time = function(milliseconds) {
    var value = milliseconds;
    return {
        concat: function(t) {
            return time(value + t.extract());
        },
        extract: function() {
            return value;
        },
        map: function(f) {
            return time(f(value));
        }
    }
}

function asSeconds(value) {
    return value / 1000;
}
function asMinutes(value) {
    return value / 1000 / 60;
}

// Implementation

var second = time(1000);
var minute = time(60000);

var minutes30 = minute.map(function(value) {
    return value * 30;
}); 

var seconds2 = second.concat(second);

seconds2.map(asSeconds).map(function(value) {
    console.log(value);
});
minutes30.map(asMinutes).map(function(value) {
    console.log(value);
});