fraction.js

function calculateOddsDecimal(a, b) {
    return (a / b);
}

function calculateOddsPercent(a, b) {
    return (calculateOddsDecimal(a, b) * 100).toFixed(2);
}

function fractionToDecimal(fraction) {
    let fractional = fraction.split('/');
    return fractional[0] / fractional[1];
}

function decimalToFraction(decimal) {
    let gcds = gcd(decimal * 100, 100);
    return `${((decimal * 100) / gcds)}/${(100 / gcds)}`;
}

function gcd(numerator, denominator) {
    if (!denominator) {
        return numerator;
    }
    return gcd(denominator, numerator % denominator);
}