摘要：``` const array = [1, 2, [1], [4], [5, 23, [23]], 12, [1, [2], [3, 4, [5], [6]]]] function flatten(arr) { return arr.reduce((a, b) => [].concat(Array.isArray(a) && a ? flatten(a) : a, Array.isArra... 阅读全文