Override method in JavaScript

override.js

var create = function (proto) {
    var F = function () {};
    F.prototype = proto;
    return new F();
};

var Point = {};
Point.initialize = function (x, y) {
    this.x = x;
    this.y = y;
    return this;
};
    
Point.asString = function () {
    return this.x + '@' + this.y;
};

function newPoint (x, y) {
    return create(Point).initialize(x, y);
}


var Circle = create(Point);
Circle.initialize = function(x, y, radius) {
    Point.initialize.call(this, x, y);
    this.radius = radius;
    return this;
};

Circle.asString = function () {
    return 'radius: ' + this.radius + ' ' + Point.asString.call(this);
};


function newCircle (x, y, radius) {
    return create(Circle).initialize(x, y, radius);
}


var p = newPoint(12, 34);
console.log(p.asString());

var c = newCircle(3, 5, 78);
console.log(c.asString());

private.js

var create = function (proto) {
    var F = function () {};
    F.prototype = proto;
    return new F();
};

var Module = function () {
    var Point = {};

    var privateTo_s =  function () {
        return this.x + '@' + this.y;
    };

    Point.initialize = function (x, y) {
        this.x = x;
        this.y = y;
        return this;
    };
    
    Point.asString = function () {
        return privateTo_s.call(this);
    };

    return {
        newPoint : function (x, y) {
            return create(Point).initialize(x, y);
        }
    }

}();

var p = Module.newPoint(12, 34);
console.log(p.asString());