  /*

  this seems to be not only shorter, but faster than
  string.replace(/\\/g, '\\\\').
            replace(/\u0008/g, '\\b').
            replace(/\t/g, '\\t').
            replace(/\n/g, '\\n').
            replace(/\f/g, '\\f').
            replace(/\r/g, '\\r').
            replace(/'/g, '\\\'').
            replace(/"/g, '\\"');
  or string.replace(/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, "\\$&")
  see http://jsperf.com/string-escape-regexp-vs-json-stringify
  */
  function srcEscape(str) {
    var a = {};
    a[str] = 1;
    return JSON.stringify(a).slice(1,-3);
  }

module.exports.srcEscape = srcEscape;
