HORIZON PROJECT

var baseToString = require('./_baseToString'),

    castSlice = require('./_castSlice'),

    charsEndIndex = require('./_charsEndIndex'),

    charsStartIndex = require('./_charsStartIndex'),

    stringToArray = require('./_stringToArray'),

    toString = require('./toString');

/** 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 && (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('');

}

module.exports = trim;