#命令模式(Command)

let add = (...rest) => rest.reduce((total, num) => total + num);
let sub = (a, b) => a - b;
let mul = (a, b) => a * b;
let div = (a, b) => a / b;

class Calculator {
  constructor() {}
  add(...rest) {
    return add(...rest);
  }
  sub(a, b) {
    return sub(a, b);
  }
  mul(a, b) {
    return mul(a, b);
  }
  div(a, b) {
    return div(a, b);
  }
}

export default Calculator;

calculator.add(2, 4, 5);
calculator.sub(22, 13);
calculator.mul(3, 7);
calculator.div(9, 3);