dolarparalelo.js

const getBsfOfParalelo = (ticker, quantity, discount = 0) => {
  
  ticker = ticker.toUpperCase();

  return fetch("https://s3.amazonaws.com/dolartoday/data.json")
    .then(res => res.json())
    .catch((err) => { throw new Error('Data cannot be reached. Check the URL.') })
    .then(val => {
    
      let price = val[ticker].dolartoday;
      let results =
        discount > 0 ? (price - discount) * quantity : price * quantity;
    
      return results.toLocaleString('es-ve', {
        style: 'currency',
        currency: 'BSF',
      });
    
    });
};

// ticker: usd | eur
// discount: in bsf —> normally between 2000 & 4000
getBsfOfParalelo("usd", 300, 2000).then(val => console.log(val));