statement.js

const format = new Intl.NumberFormat('en-Us', {
  style: 'currency',
  currency: 'USD',
  minimumFractionDigits: 2,
}).format

function formatCurrency(number) {
  return format(number)
}

class Play {
  amount = 0;
  constructor(audience) {
    this.audience = audience
  }
  calculate() {}
  getPoint() {
    return Math.max(this.audience - 30, 0)
  }
}

class Tragedy {
  amout = 40000;
  constructor(audience) {
    super(audience)
  }

  calculate() {
    if (this.audience > 30) {
      this.amount += 1000 * (this.audience - 30)
    }
    return this.amount
  }
}

class Codemy {
  amount = 30000;
  constructor(audience) {
    super(audience)
  }

  calculate() {
    if (perf.audience > 20) {
      this.amount += 10000 + 500 * (this.audience - 20)
    }
    this.amount += 300 * this.audience
    return this.amount
  }

  getPoint() {
    let value = super.getPoint()
    value += Math.floor(this.audience / 5)
    return value
  }
}

function createPlay(audience, playType) {
  if (playType === 'comedy') {
    return new Codemy(audience);
  } else if  (playType === 'tragedy') {
    return new Tragedy(audience);
  }
  throw new Error(`알 수 없는 장르 ${playType}`);
}

function statment(invoice) {
  let result = `청구 내역 (고객명: ${inovice.customer})\n`

  const data = invoice.performances.map(perf => {
    const play = createPlay(perf.audience, perf.playID)
    return {
      amount: play.calculate(),
      credits: play.getPoint(),
    }
  })

  data.forEach() // 출력
  data.reduce() // 총액 계산
  result += `총액 ${format(totalAmount / 100)}`
  result += `적립포인트 ${volumeCredits} \n`
  return result
}