I know this is simple but I am JavaScript / CSS challenged so I'm writing it down because I've had continuous problems with it in the past and I know that this solution works for Bootstrap 4.

Let's say that you have a div that you want hidden and only displayed by a button when you click it. Here's the solution:

<a href="#feeds" class="btn btn-default" data-toggle="collapse">Toggle Feeds</a>
<div id="feeds" class="collapse">
    This div (feeds) is hidden by default.

Here's how this works:

  1. Add a div named feeds around the content you want hidden. This needs to have a class named collapse added to it because its default display state is collapsed.
  2. Add an A tag with an href of "#feeds" above the content and a data-toggle named collapse.
  3. When the user clicks the A tag then the a tag's data-toggle will be applied to the matching div.

Thank you to this Stack Overflow post.