var escapeHtmlChar = require('./_escapeHtmlChar'),

toString = require('./toString');

/** Used to match HTML entities and HTML characters. */ var reUnescapedHtml = /[&<>“']/g,

reHasUnescapedHtml = RegExp(reUnescapedHtml.source);

/**

* Converts the characters "&", "<", ">", '"', and "'" in `string` to their
* corresponding HTML entities.
*
* **Note:** No other characters are escaped. To escape additional
* characters use a third-party library like [_he_](https://mths.be/he).
*
* Though the ">" character is escaped for symmetry, characters like
* ">" and "/" don't need escaping in HTML and have no special meaning
* unless they're part of a tag or unquoted attribute value. See
* [Mathias Bynens's article](https://mathiasbynens.be/notes/ambiguous-ampersands)
* (under "semi-related fun fact") for more details.
*
* When working with HTML you should always
* [quote attribute values](http://wonko.com/post/html-escaping) to reduce
* XSS vectors.
*
* @static
* @since 0.1.0
* @memberOf _
* @category String
* @param {string} [string=''] The string to escape.
* @returns {string} Returns the escaped string.
* @example
*
* _.escape('fred, barney, & pebbles');
* // => 'fred, barney, &amp; pebbles'
*/

function escape(string) {

string = toString(string);
return (string && reHasUnescapedHtml.test(string))
  ? string.replace(reUnescapedHtml, escapeHtmlChar)
  : string;

}

module.exports = escape;