eloquent.js

function Point(x, y, proto) {
  var p = Object.create(proto || Point.prototype);
  
  p.x = x;
  p.y = y;
  
  return p;
};

Point.prototype = {
  plus: function(point) {
    this.x += point.x;
    this.y += point.y;
    
    return this;
  }, 
  minus: function(point) {
    this.x -= point.x;
    this.y -= point.y;
    
    return this;
  },
  get distance() {
    return Math.sqrt((this.x * this.x) + (this.y * this.y));
  }
};


console.log(Point(1, 2).plus(Point(2, 3)));
// → Point{x: 3, y: 5}
console.log(Point(1, 2).minus(Point(2, 3)));
// → Point{x: -1, y: -1}
console.log(Point(3, 4).distance);
// → 5