var makeString = require('./helper/makeString');
  var defaultToWhiteSpace = require('./helper/defaultToWhiteSpace');
  var nativeTrim = String.prototype.trim;
  
  module.exports = function trim(str, characters) {
    str = makeString(str);
    if (!characters && nativeTrim) return nativeTrim.call(str);
    characters = defaultToWhiteSpace(characters);
    return str.replace(new RegExp('^' + characters + '+|' + characters + '+$', 'g'), '');
  };