(()=>{
  //定义一个接口
  interface iPerson{
    firstName: string
    lastName: string
  }
  //输出名字
  function showFullName(person:iPerson){
    return person.firstName + '_' + person.lastName
  }
  //定义一个对象
  const person = {
    firstName: '山东',
    lastName: '蓝翔'
  }
  console.log(showFullName(person))
})()