To all the JavaScript developers out there (beginners and more experienced): what's a JavaScript concept that still confuses you? Don't be shy and share your thoughts!

I asked the same question on Twitter and Linkedin, I've got:

"Not a beginner, but closures are still kinda hard"

"destructing. Still a bit tricky when it comes to reassign an object inside an object"

"Dynamically adding elements to the DOM but it looks like React makes doing things in vanilla unnecessary"

And how about you?