FreecurrencyAPI - Get Exchange rate (Google Apps Script)

GET_EXCHANGE_RATE.gs

/**
 * 
 * @param baseCurrency string - Ex. "USD"
 * @param exchangeCurrency string - Ex. "EUR"
 * @param refreshCache boolean - Default false
 * @returns number - Ex. 0.95
 */
function GET_EXCHANGE_RATE(baseCurrency, exchangeCurrency, refreshCache = false) {
  const exchangeRateCacheKey = 'exchange_rate' + '_' + baseCurrency + '_' + exchangeCurrency
  const cache = CacheService.getScriptCache();

  if(!refreshCache){
    const cached = cache.get(exchangeRateCacheKey);

    if (cached != null) {
      return cached;
    }
  }

  const scriptProperties = PropertiesService.getScriptProperties();
  const api_key = scriptProperties.getProperty("api_key"); // Store it in the project's settings
  
  const url = 'https://api.freecurrencyapi.com/v1/latest?'
    + 'apikey=' + api_key
    + '&base_currency=' + baseCurrency
    + '&currencies=' + exchangeCurrency;

  const response = UrlFetchApp.fetch(url, {
    method: "GET",
    contentType: "application/json",
  });

  const { data } = JSON.parse(response.getContentText());
  const exchangeRate = data[exchangeCurrency];

  cache.put(exchangeRateCacheKey, exchangeRate, 86400); // 1 day

  return exchangeRate;
}