Tuple

1. 고정된 길이의 배열

2. 고정된 타입의 배열

role: [number, string];
// tuple type

Tuple

let arr: [string, number] = ["hi", 10];

arr[1].concat("!"); // Error, 'number' does not have 'concat'
arr[5] = "hello"; // Error, Property '5' does not exist on type '[string, number]'

let myList: [number, string] = [
  [1, "Steve"],
  [2, "Bill"],
  [3, "Jeff"],
];

myList.push([4, "HUN"]);