const convertCurrency = (from, to, amount) => {
  const countries = getCountries(to);
  const rate = getExchangeRate(from, to);
  return Promise.all([countries, rate])
    .then(([countries, rate]) => {
    const exchangedAmount = amount * rate
    return `${amount} ${from} is worth ${exchangedAmount} ${to}. ${to} can be used in the following countries: ${countries.join(', ')}`
  })
}

convertCurrency('CAD', 'USD', 100).then((status) => {
  console.log(status)
})