Javascript使包含未知数据和未知数量的数组的数组长度相等

const arr = [[1, 2, 3], [4, 5], [6, 7, 8, 9]];

const maxLength = arr.reduce((acc, curr) => Math.max(acc, curr.length), 0);

console.log(maxLength); // 输出：4

const arr = [[1, 2, 3], [4, 5], [6, 7, 8, 9]];

const lengths = arr.map(subArr => subArr.length);
const maxLength = Math.max(...lengths);

console.log(maxLength); // 输出：4

const arr = [[1, 2, 3], [4, 5], [6, 7, 8, 9]];

let maxLength = 0;
for (let i = 0; i < arr.length; i++) {
  if (arr[i].length > maxLength) {
    maxLength = arr[i].length;
  }
}

console.log(maxLength); // 输出：4