gistfile1.js

var cardJSON1 = {
    text:'this is text',
    color:'red',
    position:{
        x:200,
        y:200
    }
};

var cardJSON2 = {
    text:'this is text',
    color:'green',
    position:{
        x:200,
        y:200
    }
};
 
var Card = function(obj){
    var that = this;
    var props = Object.getOwnPropertyNames(obj);
    props.forEach(function(prop){
        var propDescriptor = Object.getOwnPropertyDescriptor(obj, prop);
        that[prop] = propDescriptor.value
    });
};

Card.prototype.setColor = function(color){
    //console.log(this.color);
    this.color = color;
};

Card.prototype.getColor = function(){
    return this.color;
};

var card1 = new Card(cardJSON1);
console.log(card1);
//card1.setColor.apply(card1, ['blue']);
card1.color = 'blue';
console.log(card1.getColor());
//console.log(card1.getColor.apply(card1));

var card2 = new Card(cardJSON2);
console.log(card2);
card2.setColor('pink');
console.log(card2.getColor());
//console.log(card2.getColor.apply(card1));