Javascript递归数组展平

function flattenArray(arr) {
  let result = [];
  for (let i = 0; i < arr.length; i++) {
    if (Array.isArray(arr[i])) {
      result = result.concat(flattenArray(arr[i]));
    } else {
      result.push(arr[i]);
    }
  }
  return result;
}

// 示例
const nestedArray = [1, [2, [3, 4], 5], 6];
console.log(flattenArray(nestedArray)); // 输出: [1, 2, 3, 4, 5, 6]

const nestedArray = [1, [2, [3, 4], 5], 6];
const flattenedArray = nestedArray.flat(Infinity);
console.log(flattenedArray); // 输出: [1, 2, 3, 4, 5, 6]

function flattenArrayIterative(arr) {
  const stack = [...arr];
  const result = [];
  while (stack.length) {
    const next = stack.pop();
    if (Array.isArray(next)) {
      stack.push(...next);
    } else {
      result.push(next);
    }
  }
  return result.reverse();
}

// 示例
const nestedArray = [1, [2, [3, 4], 5], 6];
console.log(flattenArrayIterative(nestedArray)); // 输出: [1, 2, 3, 4, 5, 6]