…arr 可以将一个数组展开

    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.     <script>
    10.         //  ...arr  可以将一个数组展开
    11.         var arr = [1,2,3];
    12.         console.log(arr);
    13.         console.log(...arr);
    14.         var a = [4,5,6];
    15.         var b = [7,8,9];
    16.         a.push(...b);
    17.         console.log(a);
    18.     </script>
    19. </body>
    20. </html>

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