gwanhyeong

class Trader {
  String name;
  String city;
  Trader(this.name, this.city);
}

class Transaction {
  Trader trader;
  int year;
  int value;

gwanhyeong

const Prime = (function () {
  function Prime(number = 0) {
    this.number = number;
    this.factorSet = this.factors();
  }
  
  Prime.prototype.toString = function() {
    return this.number;
  }