long.js

// *SMELL*
function convertTemperatures(farenheit, celcius, kelvin) {
  const farenheitToCelcius = (5 / 9) * (farenheit - 32);
  const farenheitToKelvin = ((farenheit - 32) / 1.8) + 273.15;

  const celciusToFarenheit = (celcius * 1.8) + 32;
  const celciusToKelvin = celcius + 273.15;

  const kelvinToFarenheit = kelvin * 1.8 - 459.67;
  const kelvinToCelcius = kelvin - 273.15;

  return {
    farenheitConversion: {
      farenheitToCelcius,
      farenheitToKelvin
    },
    celciusConversion: {
      celciusToFarenheit,
      celciusToKelvin
    },
    kelvinConversion: {
      kelvinToFarenheit,
      kelvinToCelcius
    }
  }
}

// *REFACTORED*
function farenheitConversion(farenheit) {
  const toCelsius = (5 / 9) * (farenheit - 32);
  const toKelvin = ((farenheit - 32) / 1.8) + 273.15;
  return {toCelsius, toKelvin};
}

function celciusConversion(celcius) {
  const toFarenheit = (celcius * 1.8) + 32;
  const toKelvin = celcius + 273.15;
  return {toFarenheit, toKelvin};
}

function kelvinConversion(kelvin) {
  const toFarenheit = kelvin * 1.8 - 459.67;
  const toCelcius = kelvin - 273.15;
  return {toFarenheit, toCelcius};
}

function convertTemperatures(farenheit, celcius, kelvin) {
  return {
    farenheit: farenheitConversion(farenheit),
    celcius: celciusConversion(celcius),
    kelvin: kelvinConversion(kelvin)
  }
}