Check out example codes for "foundation 5 dropdown alignment". It will help you in understanding the concepts better.

Code Example 1

<!-- Depending on how your dropdown is structured -->
<a
  data-dropdown="drop1"
  aria-controls="drop1"
  aria-expanded="false"
  data-options="align:left">
  Has Dropdown
</a>
<!-- OR -->
<ul
  id="drop1"
  class="f-dropdown drop-left"
  data-dropdown-content aria-hidden="true"
  tabindex="-1">
  <li><a href="#">This is a link</a></li>
  <li><a href="#">This is another</a></li>
  <li><a href="#">Yet another</a></li>
</ul>

Learn ReactJs, React Native from akashmittal.com