Function _toPropertyKey

client-dist/socket.io.js:266–269

(arg)

    return (hint === "string" ? String : Number)(input);
  }
  function _toPropertyKey(arg) {
    var key = _toPrimitive(arg, "string");
    return typeof key === "symbol" ? key : String(key);
  }

  var PACKET_TYPES = Object.create(null); // no Map = no polyfill
  PACKET_TYPES["open"] = "0";