code: function trim(string, chars, guard) {
        string = toString(string);
        if (string && (guard || chars === undefined)) {
          return string.replace(reTrim, '');
        }
        if (!string || !(chars = baseToString(chars))) {
          return string;
        }
        var strSymbols = stringToArray(string),
            chrSymbols = stringToArray(chars),
            start = charsStartIndex(strSymbols, chrSymbols),
            end = charsEndIndex(strSymbols, chrSymbols) + 1;
  
        return castSlice(strSymbols, start, end).join('');
      }
docs: Removes leading and trailing whitespace or specified characters from `string`.
  
  @static
  @memberOf _
  @since 3.0.0
  @category String
  @param {string} [string=''] The string to trim.
  @param {string} [chars=whitespace] The characters to trim.
  @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
  @returns {string} Returns the trimmed string.
  @example
  
  _.trim('  abc  ');
  // => 'abc'
  
  _.trim('-_-abc-_-', '_-');
  // => 'abc'
  
  _.map(['  foo  ', '  bar  '], _.trim);
  // => ['foo', 'bar']