minimize requests

[mFlaifel]

• what will happen when the value is empty and the user focusout from the input field => send an unnecessary request. https://github.com/GSG-G9/Currency-Xchange/blob/89b2dc7addb7158068585228a7e65002aaf76b58/js/dom.js#L35-L38
• I suggest at least make a validation on the input value:

  exchangeFrom.addEventListener('focusout', () => { 
   if (exchangeFrom.value) {
   GenericXHR(`https://restcountries.eu/rest/v2/name/${exchangeFrom.value}`,countryFunc1) 
  }
  });