If you find something you don’t know or aren’t quite sure about, you should be a pro by now at Googling your way to an answer, looking at docs, and cruising through Stack Overflow posts. You’ve got all the tools you need to be a developer. And, really, the big secret is that you’ve been a web developer for a long time already.
So where do you go from here? BUILD! Build and build and build and build (see a theme in this curriculum yet?). Use what you’ve learned to create great projects. Get a job so someone else pays you to build. But focus on creating interesting software and using that to drive your education.
There’s a whole world of additional things you can learn — D3 for data visualization, other full-stack frameworks or single-page MVC front-end frameworks… all that stuff is best learned when you’ve got something you want to build that requires "the perfect tool for the job."
And speaking of jobs, if you’ve made it this far then you’ve displayed the kind of capability and drive that employers are looking for. The final step is to show that to the world and get them to pay you to keep learning.