TypeScript get 与 set 的使用

class Person {
  // 姓氏
  firstName: string
  // 名字
  lastName: string
  // 信息
  private _age: number = 20 
  // 构造方法
  constructor(firstName: string, lastName: string) {
    this.firstName = firstName
    this.lastName = lastName
  }
  // 读取(get)
  get fullName () {
    return this.firstName + '-' + this.lastName
  }
  // 设置(set)
  set fullName (val) {
    let names = val.split('-')
    this.firstName = names[0]
    this.lastName = names[1]
  }
  // 获取年龄
  get age (): number {
    return this._age
  }
  // 设置年龄，支持修饰符，不写默认就是 public
  public set age (val) {
    this._age = val
  }
}