Calculate profit through chain methods

calculator.js

export default class Calculator {
  constructor() {
    this.value = 0;
  }

  revenue(value) {
    this.value = value;
    return this;
  }

  deductTax(percentage) {
    this.value = this.value - (percentage * this.value) / 100;
    return this;
  }

  // EU VAT convenience method
  deductVAT(percentage = 20) {
    return this.deductTax(percentage);
  }

  // UK Corporation tax convenience method
  deductCorpTax(percentage = 20) {
    return this.deductTax(percentage);
  }

  deductCost(value) {
    this.value = this.value - value;
    return this;
  }
}

// const a = new Calculator()
//   .revenue(1250)
//   .deductVAT()
//   .deductCorpTax();
// console.log(a.value);

// Console Output
// 800