JS Class example

js-class-example.js

// Class definition / constructor
var Vehicle = (function() {

    /** @const */ var SPEED_LIMIT = 5;
    
    /**
     * A vehicle.
     * 
     * @constructor
     * @this {Vehicle}
     * @param {string} color Vehicle color.
     * @param {number} initSpeed Vehicle's initial speed.
     */
    var _Vehicle = function(color, initSpeed) {
        // Initialization
        this._color = color;

        // Other member vars
        this._speed = 0;

        if (initSpeed)
            this._speed = initSpeed;
    }
    
    _Vehicle.staticMethod = function () { alert('hello world')};
    
    // "Class"-wide methods.
    _Vehicle.prototype = {
        /**
         * Returns the status of the vehicle.
         * 
         * @this {Vehicle}
         * @return {string} The status.
         */
        getStatus: function () {
            var text;

            // ok
            if (this._speed > SPEED_LIMIT) {
                return "Over the speed limit! Color: " + this._color + " Speed: " + this.getSpeed();			
            }
            return "Vroom! Color: " + this._color + " Speed: " + this.getSpeed();
        },
        
        /**
         * Speeds up the vehicle.
         * 
         * @this {Vehicle}
         * @amount {number} The amount to speed it up.
         */
        speedUp: function (amount) {
            if (amount)
                this._speed += amount;
            else
                this._speed++;
            return this._speed;
        },
        /**
         * Slows down the vehicle.
         * 
         * @this {Vehicle}
         * @amount {number} The amount to slow it up.
         */
        slowDown: function (amount) {
            if (amount)
                this._speed -= amount;
            else
                this._speed--;
            return this._speed;
        },
        /**
         * Gets the current speed of the vehicle.
         * 
         * @this {Vehicle}
         * @return {number} The current speed of the vehicle.
         */
        getSpeed: function() { return this._speed; }
    };
    return _Vehicle;
})();


// Instance methods

//console.log(test.Vehicle);
var v1 = new Vehicle('blue', 10);
var v2 = new Vehicle('red');

v1.speedUp();
v1.speedUp();
v1.speedUp();

v2.slowDown();
v2.slowDown();
v2.slowDown();

console.log(v1.getStatus());
console.log(v2.getStatus());
console.log(v2.getSpeed());

Vehicle.staticMethod();

// console.log(SPEED_LIMIT); // Error, not defined outside of closure