index.js

/**
 * JSON parse.
 *
 * @see Based on jQuery#parseJSON (MIT) and JSON2
 * @api private
 */

var rvalidchars = /^[\],:{}\s]*$/;
var rvalidescape = /\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g;
var rvalidtokens = /"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g;
var rvalidbraces = /(?:^|:|,)(?:\s*\[)+/g;
var rtrimLeft = /^\s+/;
var rtrimRight = /\s+$/;

module.exports = function parsejson(data) {
  if ('string' != typeof data || !data) {
    return null;
  }

  data = data.replace(rtrimLeft, '').replace(rtrimRight, '');

  // Attempt to parse using the native JSON parser first
  if (global.JSON && JSON.parse) {
    return JSON.parse(data);
  }

  if (rvalidchars.test(data.replace(rvalidescape, '@')
      .replace(rvalidtokens, ']')
      .replace(rvalidbraces, ''))) {
    return (new Function('return ' + data))();
  }
};