lodash/trim.js

define(['./_charsEndIndex', './_charsStartIndex', './_stringToArray', './toString'], function(charsEndIndex, charsStartIndex, stringToArray, toString) {

  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
  var undefined;

  /** Used to match leading and trailing whitespace. */
  var reTrim = /^\s+|\s+$/g;

  /**
   * 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']
   */
  function trim(string, chars, guard) {
    string = toString(string);
    if (!string) {
      return string;
    }
    if (guard || chars === undefined) {
      return string.replace(reTrim, '');
    }
    chars = (chars + '');
    if (!chars) {
      return string;
    }
    var strSymbols = stringToArray(string),
        chrSymbols = stringToArray(chars);

    return strSymbols
      .slice(charsStartIndex(strSymbols, chrSymbols), charsEndIndex(strSymbols, chrSymbols) + 1)
      .join('');
  }

  return trim;
});