Acts_as_commentable_with_threading javascript toggle not working with rails 5

I've been trying to get this tutorial to work with my rails 5 project, but apparently there has been some change in javascript since rails 4, which causes the reply field to immediately close upon clicking "reply". It's supposed to stay open until you've typed in a message and clicked the "Post comment" button next to it.
There is a comment from 6 days ago suggesting js code that works with rails 5, but it does not work for me. (do I have to change something with the anchor and span he mentions?)

I have followed the guide exactly, even made an entirely new project, and still no luck.

What change needs to be made to the javascript code to make it compatible with rails 5?