判断对象属性是否存在的方法

方式一 in

  1.     let person = {
  2.         "name": "wuhua",
  3.         "age": 18
  4.     }
  5.     console.log('name' in person)
  6.     console.log('fafa' in person)

方式二 hasOwnProperty

  1.     let person = {
  2.         "name": "wuhua",
  3.         "age": 18
  4.     }
  5.     console.log(person.hasOwnProperty('name'))
  6.     console.log(person.hasOwnProperty('haha'))