Comment prefix for kernel gateway

[Andrew C]

I am trying to set the comment prefix for a kernel gateway running the IJavascript kernel so I can expose cells for API calls. Right now, the setting in my config file looks like this:

c.NotebookHTTPPersonality.comment_prefix = {'javascript': '//', None: '#'}

It is working fine with the IPython notebook when I add annotations for API endpoints, but when I try to start a kernel gateway for an IJavascript notebook, the kernel gateway fails to run and says "No endpoints were discovered". How do I make sure the kernel gateway is properly mapping languages to comment prefixes?