const overloadPeriods = { // en: [[15, 24]], pl: [[0, 24]], }; module.exports = (locale, timestamp = new Date) => { if (overloadPeriods[locale] === undefined) { return false; } for (let [periodStart, periodEnd] of overloadPeriods[locale]) { if (timestamp.getUTCHours() >= periodStart && timestamp.getUTCHours() < periodEnd) { return true; } } return false; }