class BaseClass {

    constructor() {}

}

​

class Point extends BaseClass {

    constructor(x, y) {

        super();

        this.x = x;

        this.y = y;

    }

​

    add(point) {

        return new Point(this.x + point.x, this.y + point.y);

    }

​

    sub(point) {

        return new Point(this.x - point.x, this.y - point.y);

    }

}

var Point1 = Point;

​

var p1 = new Point1(10, 10);

var p2 = new Point1(10, -10);

var sum = p1.add(p2);

var dif = p1.sub(p2);

function BaseConstructor() {}

​

function Point2(x, y) {

    this.x = x;

    this.y = y;

}

​

Point2.prototype.add = function(point) {

    return new Point2(this.x + point.x, this.y + point.y);

}

​

Point2.prototype.sub = function(point) {

    return new Point2(this.x - point.x, this.y - point.y);

}

​

Object.setPrototypeOf(Object.setPrototypeOf(Point2, BaseConstructor).prototype, BaseConstructor.prototype);

​

var p1 = new Point2(10, 10);

var p2 = new Point2(10, -10);

var sum = p1.add(p2);

var dif = p1.sub(p2);

function PointX(x, y) {

    return {}

}

​

function Point3(x, y) {

    return {

        ...PointX(x, y),

        x,

        y,

        add: (point) => Point3(x + point.x, y + point.y),

        sub: (point) => Point3(x - point.x, y - point.y)

    }

}

​

var p1 = new Point3(10, 10);

var p2 = new Point3(10, -10);

var sum = p1.add(p2);

var dif = p1.sub(p2);