将数组的数组转换为单个数组

const nestedArray = [[1, 2], [3, 4], [5, 6]];
const flattenedArray = nestedArray.flat();

console.log(flattenedArray);
// 输出: [1, 2, 3, 4, 5, 6]

const nestedArray = [[1, 2], [3, [4, 5]], [6, [7, [8, 9]]]];
const flattenedArray = nestedArray.flat(1);

console.log(flattenedArray);
// 输出: [1, 2, 3, [4, 5], 6, [7, [8, 9]]]

function flattenArray(arr) {
  return arr.reduce((result, current) => {
    if (Array.isArray(current)) {
      return result.concat(flattenArray(current));
    } else {
      return result.concat(current);
    }
  }, []);
}

const nestedArray = [[1, 2], [3, [4, 5]], [6, [7, [8, 9]]]];
const flattenedArray = flattenArray(nestedArray);

console.log(flattenedArray);
// 输出: [1, 2, 3, 4, 5, 6, 7, 8, 9]