Accessing private member variables from prototype-defined functions

Question

Is there any way to make “private” variables (those defined in the constructor), available to prototype-defined methods?

TestClass = function(){
    var priv         


        

Answer 1

Try it!

    function Potatoe(size) {
    var _image = new Image();
    _image.src = 'potatoe_'+size+'.png';
    function getImage() {
        if (getImage.caller == null || getImage.caller.owner != Potatoe.prototype)
            throw new Error('This is a private property.');
        return _image;
    }
    Object.defineProperty(this,'image',{
        configurable: false,
        enumerable: false,
        get : getImage          
    });
    Object.defineProperty(this,'size',{
        writable: false,
        configurable: false,
        enumerable: true,
        value : size            
    });
}
Potatoe.prototype.draw = function(ctx,x,y) {
    //ctx.drawImage(this.image,x,y);
    console.log(this.image);
}
Potatoe.prototype.draw.owner = Potatoe.prototype;

var pot = new Potatoe(32);
console.log('Potatoe size: '+pot.size);
try {
    console.log('Potatoe image: '+pot.image);
} catch(e) {
    console.log('Oops: '+e);
}
pot.draw();