As a side note, in editors using js/ts language server from VSCode, you can benefit from these types even in "vanilla" JavaScript with JSDoc. It could look like:
// @ts-check
/// <reference path="./ts-reset-0.3.7/src/entrypoints/recommended.d.ts"/>
// = contents of the archive from
// https://github.com/total-typescript/ts-reset/releases
const allCurrencies = /** @type {const} */(["EUR", "USD"]);
/**
* @typedef {typeof allCurrencies[number]} currency
*/
allCurrencies.includes('XXX');
// No 'Argument of type '"XXX"' is not assignable…' error any more.
// Would be that error without ts-reset.
/** @type {currency} */
let foo = 'EUR'; // OK
/** @type {currency} */
let bar = 'XXX'; // that error, expected
