tuenti_secure JSON parser

gistfile1.js

function tuenti_secure(string) {
  var regexp1 = /^[,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t]*$/,
    regexp2 = /\\./g,
    regexp3 = /"[^"\\\n\r]*"/g;
  if (!string || typeof string !== "string") {
    return null;
  }
  if (regexp1.test(string.replace(regexp2, "@").replace(regexp3, ""))) {
    return null;
  }
  return eval("(" + string + ")");
}