TypeScriptでタプルへの型推論を行う方法 ref: https://qiita.com/kurogelee/items/12c45f9fb1615877a61f

notuple.ts

const tupleStrNum = ["X", 2]; // (string|number)[]

tuple.ts

import { tuple } from "./util";

const tupleStrNum = tuple("X", 2); // [string, number]

util.ts

export function tuple<T1, T2>(t1: T1, t2: T2): [T1, T2];
export function tuple<T1, T2, T3>(t1: T1, t2: T2, t3: T3): [T1, T2, T3];
export function tuple(...args: any[]) {
    return args;
}