在node.js中创建链式方法？

function Calculator() {
  this.value = 0;
}

Calculator.prototype.add = function(num) {
  this.value += num;
  return this;
};

Calculator.prototype.subtract = function(num) {
  this.value -= num;
  return this;
};

Calculator.prototype.multiply = function(num) {
  this.value *= num;
  return this;
};

Calculator.prototype.divide = function(num) {
  this.value /= num;
  return this;
};

Calculator.prototype.getResult = function() {
  return this.value;
};

// 使用示例
const calculator = new Calculator();
const result = calculator.add(5).multiply(2).subtract(3).divide(2).getResult();
console.log(result); // 输出: 4