操作数组对象

给每一个对象添加一条数据

const arr = [
    {name: '张三', age: 18},
    {name: '李四', age: 20},
]
 
 
this.arr.forEach(item => {
    this.$set(item, 'selected', false)
})
 
// 结果
[
    {name: '张三', age: 18, selected: false},
    {name: '李四', age: 20, selected: false}
]