Gist from mistakes.io

index.js

function Point(x, y) {
  this.x = x;
  this.y = y;
}
Point.prototype.dist = function dist(p) {
  return Math.sqrt(Math.pow(Math.abs(this.x - p.x), 2)
    + Math.pow(Math.abs(this.y - p.y), 2));
}
Point.prototype.toString = function() {
  return '(' + this.x + ',' + this.y + ')'
}
function Point3d(x, y, z) {
  Point.call(this, x, y)
  this.z = z
}
Point3d.prototype = Object.create(Point.prototype)
Point3d.prototype.dist = function dist(p) {
  return Math.sqrt(Math.pow(Math.abs(this.x - p.x), 2)
    + Math.pow(Math.abs(this.y - p.y), 2)
    + Math.pow(Math.abs(this.z - (p.z || 0)), 2));
}
Point3d.prototype.toString = function() {
  return '(' + this.x + ',' + this.y + ',' + this.z + ')'
}

function Line(p1, p2) {
  this.start = p1;
  this.end = p2;
}
Line.prototype.toString = function() {
  return '[' + this.start + '-' + this.end + ' <' + this.length + '>' + ']'
}
Object.defineProperty(Line.prototype, 'length', {
  configurable: true,
  enumerable: true,
  get: function() {
    return this.start.dist(this.end);
  }
});