you are creating a brand new list of 4 allocated nodes when concatenating 2 lists of 2 nodes each, instead of reusing the latter 2.

Любой цикл можно

Updated to Node v12

JS: Node v12 should be used enabled along with its appropiate assertion tools (Mocha + Chai).
Refer to this and this

не спится ночью?)

appreciate your help

Reduce всем в помощь.
При прочих равных условиях часто выбрасывает AssertionError. Be careful..
Pls, write some new cases

No random tests.

Nice way to practice looking for a specific nested property at any depth. I learned a lot!

I have the same problem and I really don't understand what exactly may be wrong. Has anyone solved it?

All tests passed
One error:
TypeError: Cannot read property 'e' of undefined

Any clue?

Is the obj being tested different from the obj in the description?

Edit: yes, it is.

Could it be the function was returning undefined when it should have returned an object?

Anyway it seems to work now.

It's not fault of catch statement. If you change e to any other variable, it still show the same error involving 'e'.