刚写

[1596944197]

` var arr = [[1, 2, 2], [3, 4, 5, 5], [6, 7, 8, 9, [11, 12, [12, 13, [14]]]], 10]

function flat(arr) {
    if (typeof arr !== 'object') return arr
    let result = []
    for (let i = 0; i < arr.length; i++) {
        if (arr[i] instanceof Array) {
            result.push(...flat(arr[i]))
        } else {
            result.push(arr[i])
        }
    }
    return result
}

`