If I type the following
Mathematica returns nothing. Requesting
Information[%] seems to indicate that the operation
$Failed. I have looked at the messages window and in the terminal window, but nothing seems to be output?
After some checking, my belief is that there is no easy way to have
console.log do something like
console.log is built to have a side effect - writing to the equivalent of 'stdout' - and that stream isn't a thing you can access from the notebook interface.
console.log doesn't return anything, and so, you don't see output.
Edit: According to M.R.'s answer, this now works in 12.1. 👍👍