JS CreateRoom plugins

I'm trying to create new room by js sdk 4.0.0.5

In docuentation says I can set plugin name in room options by
roomOptions.Plugins = new string[]

But I don't see it in photon-javascript_SDK.js-file
LoadBalancingClient.prototype.createRoom = function (roomName, options)

I'm trying to put
createRoom("name", {plugins: "MyPlugin"})
or
createRoom("name", {customGameProperties: {plugins: "MyPlugin"}})
but it's not work

My factory is

public IGamePlugin Create(IPluginHost gameHost, string pluginName, Dictionary<string, string> config, out string errorMsg)
        {
            gameHost.LogWarning("!!!: > " + pluginName + " <<");

            IGamePlugin plugin;
            switch (pluginName)
            {
                case "MyPlugin":
                    plugin = new MyPlugin();
                    break;
                default:
                    plugin = new PluginBase(); // default
                    break;
            }
            return plugin.SetupInstance(gameHost, config, out errorMsg) ? plugin : null;
        }

always empty in pluginName. Am I doing something wrong?