4.4forEach（）遍历改变原结构

 <script src="https://cdn.bootcss.com/vue/2.6.10/vue.js"></script>

 <script>
        /* forEach可以改变数组的结构 */
        var obj=[{name:'wang',checked:true},{name:'li',checked:false}];
        obj.forEach(item=>item.checked=true)
        console.log(obj)    //   var obj=[{name:'wang',checked:true},{name:'li',checked:true}];
    </script>