1. 数组扁平化

1.1 描述

实现数组扁平化

1.2 实现

function flatten(list, depth = 1) {
  if (depth === 0) return list;
  return list.reduce(
    (a, b) => a.concat(Array.isArray(b) ? flatten(b, depth - 1) : b),
    []
  );
}

const a = flatten([1, 2, 3, [4, [5, 6]]]);
const b = flatten([1, 2, 3, [4, [5, 6]]], 2);

console.log(a, b);