数字循环

作者: __鹿__ | 来源:发表于2022-03-02 11:59 被阅读0次

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>数字循环</title>
</head>
<body>
    把12345变成  12345432123454321....这样的数
    [1, 2, 3, 4, 5, 4, 3, 2, 1, 2]
    <script>
        const arr = [];
        const arr2 = [1, 2, 3, 4, 5];
        let len = arr2.length;
        const N = 10
        let flag = true
        let sub = 0

        for(let i=0; i < N; i++) {
                if(flag) {
                        sub = sub > 0 ? sub : i > len ? 1 : 0
                        arr.push(arr2[sub++])
                        if(sub === len) {
                                flag = false
                                sub = len - 2
                        }
                } else {
                        arr.push(arr2[sub--])
                        if(sub === -1) {
                                flag = true
                        }
                }
        }

console.log(arr);
    </script>
</body>
</html>