Omit middle for long string, middle version of `text-overflow: ellipsis`

omitMiddle.js

/**
 * Omit middle when a string is too long.
 * Example:
 *      ```
 *      omitMiddle('veryveryveryveryveryveryveryveryveryverylongfilename.txt')
 *      // result: 'very......name.txt'
 *      ```
 * @param str
 * @param [replacement] Default: ......
 * @param [frontCount] How many words you want to keep in the front. Default: 4
 * @param [endCount]   How many words you want to keep in the end.   Default: 8
 * @returns {string}
 */
function omitMiddle(str, replacement, frontCount, endCount) {
    frontCount = frontCount || 4;
    endCount = endCount || 8;
    replacement = replacement || '......';
    var re = new RegExp('^(.{' + frontCount + '}).{' + (replacement.length + 1) + ',}(.{' + endCount + '})$');
    return str.replace(re, '$1' + replacement + '$2');
}