Sorry to chime in while I pass through this topic, as I have the link on speed dial.
I think what @jkm345 meant, that the instruction of the lesson is coming from this newer JS track (Please confirm that @jkm345 :
Side note to @jkm345:
It’s always better/advisable to post your link to exercise, your full code, your error and learn proper markdown for your post (refer more here), that will help others to be able to help you more.
That said, I will leave in peace. Cheers