题解 | #数组扁平化#
数组扁平化
https://www.nowcoder.com/practice/5d7e0cf4634344c98e6ae4eaa2336bed
return arr.toString().split(',').map(item => item -0)
        <script>
          const _flatten = arr => {
                // 补全代码
                // console.log(...(arr.toString()));
                return arr.toString().split(',').map(item => item -0)
            }
        </script>
 
