问如何从二维数组中获取随机元素？

EN

const arr = [
 [2,3,4],
 [3,4],
 [1,22,3,45]
];

const flattenArr = arr.flat();

const randomIndex = Math.floor(Math.random()*flattenArr.length);
console.log(flattenArr[randomIndex]);

const arr = [
  [2, 3, 4],
  [3, 4],
  [1, 22, 3, 45],
];
const flatArray = arr.reduce((acc, curr) => {
  return [...acc, ...curr];
}, []);

function getRandomNumber(len) {
  return Math.floor(Math.random() * len);
}

const randomNumber = getRandomNumber(flatArray.length);
console.log(flatArray[randomNumber]);

let arr = [
 [2,3,4],
 [3,4],
 [1,22,3,45]
]


let result = [];

for(let i = 0; i < arr.length; i++){
  result.push(arr[i][Math.floor(Math.random() * arr[i].length + 0)]);
}

console.log(result);