money.js

class Money {
  constructor(amount, currency) {
    this.amount = amount;
    this.currency = currency;
  }

  times(multiplier) {
    return new Money(this.amount * multiplier, this.currency);
  }

  divide(divisor) {
    return new Money(this.amount / divisor, this.currency);
  }

  add(money) {
    if (money.currency !== this.currency) {
      throw new Error(`Cannot add ${money.currency} to ${this.currency}`);
    }

    return new Money(this.amount + money.amount, this.currency);
  }
}

module.exports = Money;