SOURCE

Array.prototype.CopySelf = function (){
   let arr = new Array()
   for(let i in this){
       arr[i] = this[i]
   }
   return arr
}
var p1 = {
	"id":"007",
	"name":"刘德华",
	"books":new Array("三国演义","红楼梦","水浒传")//这是引用类型
}
function copy(obj){
  let newObject= {}
  for(let key in obj){
      if(typeof obj[key] === 'object'){
          newObject[key] = obj[key].CopySelf()
      }else{
          newObject[key] = obj[key]
      }
  }
  return newObject
}
let a = copy(p1)
p1.id = '123'
p1.books[2] = 'ding'
console.log(p1)
console.log(a)