[Javascript]多次元配列でサイズ取得

多次元配列でサイズ取得

let userData = [
  ['a', 2, 'Tokyo'],
  ['b', 3, 'Fukuoka'],
  ['c', 4, 'Sendai']
];

let user1 = userData[0];
console.log(userData.length);
console.log(user1[0].length);

結果
3
3