index.js

function fahrenheitToCelsius(degreesFahrenheit) {
    // The equation to convert from fahrenheit to celsius is
    //  (<degrees in fahrenheit> - 32) * 5/9 = <degrees in celsius>
    let degreesCelsius;

    (degreesFahrenheit - 32) * 5/9;

    return degreesFahrenheit;
}

function celsiusToFahrenheit(degreesCelsius) {
    // The equation to convert from celsius to fahrenheit is
    //  (<degrees in celsius> * 9/5) + 32 = <degrees in fahrenheit>
    let degreesFahrenheit = (degreesCelsius * 9/5) + 32;

    return degreesFarenheit;
}

function getFirstStringFromArray(list) {
    // if list doesn't have a length property or it is 0 then it either isn't an array or
    // it is an empty array. In either case, return null.
    if (!list.length) {
        return null;
    }

    let index = 0;

    while(index < list.length) {
        if (typeof list[index] === 'string') {
            return list[index];
        }
        index++;
    }

    return null;
}


module.exports = {
    fahrenheitToCelsius,
    celsiusToFahrenheit,
    getFirstStringFromArray
}