I never said understanding, I said debugging. There are 4 implicit objects here (discounting proxies and wrappers), so unless you know them by heart, you have now idea what's in there. Then of course most debuggers will consider that one line, so to debug, you will hall have to split it in several ones to have the right to know what's going on. Plus, now that you have done it, what ? You put them back as they were ?

That's also hoping your code map files and your browser work well together, which is often not the case. Transpiled code is always a pain to debug at one point or another.

And that's just one line, a code back "full of those" will let you do the dance again and again. A very slow dance at that, cause babel is not the fastest horse in town.

Finally I'll pray your intern doesn't have to do it. But we all have teams full of good programmers right ?

But that's wishful thinking, you could be wrong about what that code does.