1  var toString = require('./toString');
 2  
 3  /**
 4   * Used to match `RegExp`
 5   * [syntax characters](http://ecma-international.org/ecma-262/7.0/#sec-patterns).
 6   */
 7  var reRegExpChar = /[\\^$.*+?()[\]{}|]/g,
 8      reHasRegExpChar = RegExp(reRegExpChar.source);
 9  
10  /**
11   * Escapes the `RegExp` special characters "^", "$", "\", ".", "*", "+",
12   * "?", "(", ")", "[", "]", "{", "}", and "|" in `string`.
13   *
14   * @static
15   * @memberOf _
16   * @since 3.0.0
17   * @category String
18   * @param {string} [string=''] The string to escape.
19   * @returns {string} Returns the escaped string.
20   * @example
21   *
22   * _.escapeRegExp('[lodash](https://lodash.com/)');
23   * // => '\[lodash\]\(https://lodash\.com/\)'
24   */
25  function escapeRegExp(string) {
26    string = toString(string);
27    return (string && reHasRegExpChar.test(string))
28      ? string.replace(reRegExpChar, '\\$&')
29      : string;
30  }
31  
32  module.exports = escapeRegExp;