I have edited my article and gave you credit as someone who came up with the method before me. I’m sorry if reading my article and using the same method discouraged you from writing further. Please, don’t stop, you are a pretty good writer. I would also be cautious about saying that you invented the method first: I have not seen anyone use it before, but it doesn’t mean nobody came up with it previously — a lot of people think alike. I really hope that you don’t jump to conclusions that somebody steals your work just because they think alike and came up with a very similar method slightly later. It is my first article too, and getting such accusation for me is also very discouraging.
I have lately been working on some Web Components (if you don’t know about Web Components, check them out) that I will eventually publish, create documentation for and will likely write Medium articles about. The real need for private properties arose because of creating those Web Components.
By the way, I noticed that even though your article describes pretty much the same method, you did not go further to explore what happens in case of inheritance. And, in case of inheritance you will encounter a problem of key mismatch when
_getPrivateData is called within a parent’s prototype. I think that even though your method is pretty much the same, you can check out my article for a solution of this problem.
Cheers, and keep writing.