It can be quite humbling to realise how large a particular field is, but it in no way makes one an 'imposter'.
Pro tip: Those 'Real Programmers' who's JS experiments make your CSS look quaint aren't the world's best programmers. They're 'yet another frontend guy' to, for example, those who write Java servers. Guess what, those writing the Java servers are 'just end-users' as far as the JVM hackers are concerned. Likewise, the JVM hackers are 'just end-users' for the OS developers. The OS developers are 'just end-users' for the hardware guys. The hardware guys are 'just making an interchangable commodity' as far as the sysadmins are concerned, as they virtualise everything away. And, of course, the frontend devs laugh at the sysadmins for not being programmers.
You might think of some Node.js guy as a demi-god, but I've never heard of him since I don't particularly care about Node.js. Likewise there were a lot of tributes being paid recently to a Ruby developer who passed away. It's touching to see how many people he'd positively impacted, but again, I've never heard of him because I don't particularly care about Ruby.
Am I an 'imposter' since I don't care about these things? Not at all. I have a high-level knowledge of what they are, and I even played around with Node.js a bit (unfortunately it was just after 0.4 had broken compatibility with most libraries in NPM!), but I can't go too far down those rabbit holes because they're not the stacks I use. Likewise, I don't expect those who are deeply into Node.js and Ruby to care about, for example, the recent death of John Reynolds, or Robert Harper's kidney transplant.
Just stick with the rabbit hole you've chosen, as long as you're enjoying it; let the work of others guide you down, and if you reach the bottom you'll suddenly find yourself to be a 'Real Programmer' who can help with the digging. Alterntively, if you disagree with or don't understand some of the decisions/conventions on the way then you should absolutely start digging in your own direction, even if it doesn't go anywhere.
PS: Knowing APIs inside-out does not make one a 'Real Programmer'. My day job is PHP, but I still tend to Google the most basic built-in functions (which, admittedly, is an artefact of PHP's poor API). You should instead strive to understand your problem inside-out, from multiple perspectives, then you can pick and choose any API/stack you like and let the docs guide you through the tedious act of plumbing it all together. Or write your own :)