Why does my link break (stop navigating to its location) when I use data-toggle attribute?

Question

I am having a play around with Bootstrap 4 in Rails 5 and I am trying to get a data-toggle to work on nav-pills.

With my code below, the

Answer 1

If by "breaking the link", you mean that browser no longer navigates to a new page, then it's because bootstrap's javascript intercepts the click on the link to do the toggling.

Clicking on a link takes you to its location, a new page. Clicking a toggle element shows/hides some other element on the current page. You can't have both.