getNumberSuffix.js

    /**
     * Returns the suffix related to the number for ex. (1st, 2nd, 3rd, 4th)
     * @param  {Number} number Number to find the suffix for.
     * @return {String}        Suffix string to append to be appended to number.
     */
    
    function getNumberSuffix(number) {
        var numberConvertedToString = (number + '');
        var lastDigit = numberConvertedToString.charAt(numberConvertedToString.length - 1);
        if (lastDigit === '1') {
            var suffix = 'st';
        } else if (lastDigit === '2') {
            var suffix = 'nd';
        } else if (lastDigit === '3') {
            var suffix = 'rd';
        } else {
            var suffix = 'th';
        }
        return suffix;
    }