4.6every（）遍历

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

<script>
        /* every只有所有条件都满足的时候才返回true */
        var obj=[{name:'wang',checked:false},{name:'li',checked:true}];
        var arr=[1,2,3,4]
        var checked=obj.every(item=>item.checked);
        var b=arr.every(item=>item>1);
        console.log(checked)     //false
        console.log(b)           //false
    </script>