Tuplas: arrays tipados de longitud fija

Bienvenida

Definir una tupla

const point: [number, number] = [10, 20];
const entry: [string, number] = ['age', 25];

Acceder a los elementos de una tupla

const pair: [string, number] = ['Alice', 30];
const name: string = pair[0]; // string
const age: number = pair[1];  // number

Desestructuración de tuplas

const [x, y]: [number, number] = [5, 10];
console.log(x + y); // 15

Tuplas frente a arrays

const arr: number[] = [1, 2, 3, 4];   // variable length
const tup: [number, string] = [1, 'a']; // fixed: 2 elements

Elementos opcionales de tuplas

type Named = [string, string?]; // name, optional nickname
const a: Named = ['Alice'];
const b: Named = ['Bob', 'Bobby'];

Elementos rest en tuplas

type StringAndNumbers = [string, ...number[]];
const data: StringAndNumbers = ['scores', 90, 85, 78];

Elementos de tupla con etiquetas

type Range = [start: number, end: number];
const r: Range = [0, 100];

Tuplas de solo lectura

const origin: readonly [number, number] = [0, 0];
// origin[0] = 5; // Error

Tuplas como valores devueltos por funciones

function useCounter(): [number, () => void] {
  let count = 0;
  return [count, () => { count++; }];
}

Inferencia de tuplas con as const

const pair = [1, 'hello'] as const;
// type: readonly [1, 'hello'] — not (number | string)[]

Comprobación rápida

Resumen