class.js

class SomeClass {
  constructor() {
    this.x = 0;
  }
  getX() {
    return this.x;
  }
  setX(val) {
    this.x = val;
  }
}

function SomeClass () {
  this.x = 0;
}

SomeClass.prototype.getX = function () {
  return this.x;
};

SomeClass.prototype.setX = function (val) {
  this.x = val;
};