indexOf与findIndex的用法

例子：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>

<body>

    <script type="text/javascript">
    var arr1 = [1, 2, 3, 4, 5]
    var arr2 = [1, 2, 4, 5]
    for (var i = 0; i < arr1.length; i++) {
        if (arr2.indexOf(arr1[i]) === -1) {
            alert(arr1[i]) //3
        }
    }
    </script>
</body>

</html>

 获取数组中某个元素的下标，如：数组中6的下标是多少

<script>
        var arr = [9,8,7,6,5,4,3,2,1]
        console.log(arr.indexOf(6)); //3
    </script>

获取数组里对象的下标,findIndex是ES6，ie浏览器不支持

<script>
        //获取数组对象里id为6的下标
        var arr = [{id:1},{id:2},{id:6},{id:8}]
        var index = arr.findIndex(item => item.id ===6);
        console.log(index); //2
    </script>

 

posted @ 2018-11-08 23:23  前端HL  阅读(1341)  评论(0)  编辑  收藏  举报