//模式一

 watch: {
          
            'obj.property': function (val) {
                 console.log('11');
            }

        },

//模式二


  'obj.property': {
        handler(newName, oldName) {
          console.log('11');
        },
    }

//监听整个数组

 obj: {
    handler(newName, oldName) {
      console.log(11');
    },

    deep: true
  }