2019.10.20

var book = {};

Object.defineProperties(book, {
    _year: {
        writable: true,
        value: 2004
    },
    edition: {
        writable: true,
        value: 1
    },
    year: {
        get: function (){
            return this._year;
        },
        set: function (newValue){
            if(newValue > 2004){
                this._year = newValue;
                this.edition += newValue - 2004;
            }
        }
    }
});