Get Programming with JavaScript

Get Programming with JavaScript - Listing 11.10

Listing 11.10 - A Counter constructor

var Counter = function () {
    var counter = 0;

    this.count = function () {
        counter = counter + 1;
        return counter;
    };
};

var peaks = new Counter();
var climbs = new Counter();

Further Adventures

Listing 11.10 - A Counter constructor - Task 2

Add a countDown method to the Counter constructor. The method should decrease the counter by 1 each time it is called.

var Counter = function () {
    var counter = 0;

    this.count = function () {
        counter = counter + 1;
        return counter;
    };

    this.countDown = function () {
        counter = counter - 1;
        return counter;
    };
};

var peaks = new Counter();
var climbs = new Counter();

Listing 11.10 - A Counter constructor - Task 3

Add a countUpBy method that counts up by a specified amont.

var Counter = function () {
    var counter = 0;

    this.count = function () {
        counter = counter + 1;
        return counter;
    };

    this.countDown = function () {
        counter = counter - 1;
        return counter;
    };

    this.countUpBy = function (amount) {
        counter = counter + amount;
        return counter;
    };
};

var peaks = new Counter();
var climbs = new Counter();