1  var baseToString = require('./_baseToString'),
 2      baseTrim = require('./_baseTrim'),
 3      castSlice = require('./_castSlice'),
 4      charsEndIndex = require('./_charsEndIndex'),
 5      charsStartIndex = require('./_charsStartIndex'),
 6      stringToArray = require('./_stringToArray'),
 7      toString = require('./toString');
 8  
 9  /**
10   * Removes leading and trailing whitespace or specified characters from `string`.
11   *
12   * @static
13   * @memberOf _
14   * @since 3.0.0
15   * @category String
16   * @param {string} [string=''] The string to trim.
17   * @param {string} [chars=whitespace] The characters to trim.
18   * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
19   * @returns {string} Returns the trimmed string.
20   * @example
21   *
22   * _.trim('  abc  ');
23   * // => 'abc'
24   *
25   * _.trim('-_-abc-_-', '_-');
26   * // => 'abc'
27   *
28   * _.map(['  foo  ', '  bar  '], _.trim);
29   * // => ['foo', 'bar']
30   */
31  function trim(string, chars, guard) {
32    string = toString(string);
33    if (string && (guard || chars === undefined)) {
34      return baseTrim(string);
35    }
36    if (!string || !(chars = baseToString(chars))) {
37      return string;
38    }
39    var strSymbols = stringToArray(string),
40        chrSymbols = stringToArray(chars),
41        start = charsStartIndex(strSymbols, chrSymbols),
42        end = charsEndIndex(strSymbols, chrSymbols) + 1;
43  
44    return castSlice(strSymbols, start, end).join('');
45  }
46  
47  module.exports = trim;