Converts numbers into a string with commas

number-to-string-comma.js

/**
 * Turns a number into a more readable format with commas
 * @param {number} num Number for conversion
 * @returns {string} Readable number such as 700,345,384
 */
function setCommas (num) {
    var letters = (num).toString().split(''),
        count = 0,
        readableNum = '';

    // Add commas where appropriate
    letters.forEach(function (l) {
        readableNum += l;
        count += 1;

        if (count !== letters.length && (letters.length - count) % 3 === 0) {
            readableNum += ',';
        }
    });

    return readableNum;
}