class Es6Point {

    constructor(x, y) {

        this.x = x;

        this.y = y;

    }

​

    add(point) {

        return new Es6Point(this.x + point.x, this.y + point.y);

    }

​

    sub(point) {

        return new Es6Point(this.x - point.x, this.y - point.y);

    }

}

​

const p1 = new Es6Point(10, 10);

const p2 = new Es6Point(10, -10);

const sum = p1.add(p2);

const dif = p1.sub(p2);

function ProtoPoint(x, y) {

    this.x = x;

    this.y = y;

}

​

ProtoPoint.prototype.add = function(point) {

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

}

​

​

ProtoPoint.prototype.sub = function(point) {

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

}

​

const p1 = new ProtoPoint(10, 10);

const p2 = new ProtoPoint(10, -10);

const sum = p1.add(p2);

const dif = p1.sub(p2);