定义一个数组 arr [1, [2, [3, [4, 5]], 6]] 将该数组变成 [1,2,3,4,5,6]

    1. let arr = [1, [2, [3, [4, 5]], 6]]
    2. let a = arr.flat(Infinity)
    3. console.log(a)
    5. let a2 = JSON.stringify(arr).replace(/\[|\]/g, '').split(',')
    6. console.log(a2)
    8. let a3 = JSON.parse(`[${JSON.stringify(arr).replace(/\[|\]/g, '')}]`)
    9. console.log(a3)
    11. let a4 = []
    12. const fn = (arr) => {
    13.   for (let i = 0; i < arr.length; i++) {
    14.     if (arr[i] instanceof Array) {
    15.       fn(arr[i])
    16.     } else {
    17.       a4.push(arr[i])
    18.     }
    19.   }
    20. }
    22. fn(arr)
    24. console.log(a4)