findIndex 对数组执行遍历,查询对应值得下标

    1. <!DOCTYPE html>
    2. <html lang="en">
    3. <head>
    4.     <meta charset="UTF-8">
    5.     <meta name="viewport" content="width=device-width, initial-scale=1.0">
    6.     <title>Document</title>
    7. </head>
    8. <body>
    9.     <!--
    10.          findIndex   对数组执行遍历,查询对应值得下标
    11.     -->
    12.     <script>
    13.         var arr = [1,2,3,2];
    14.         var index = arr.findIndex(item=>{
    15.             return item == 2;
    16.         })
    17.         console.log(index);//1
    18.     </script>
    19. </body>
    20. </html>