Q:

Uncaught TypeError: $(...).find(...).hasClass(...).show is not a function

No idea why this isn't working but I'm hoping a second set of eyes.
Yes I'm referencing the jQuery library.
var $current_selection;
$('.nav-link').hide();

$('a').click(function () {

    current_selection = $(this).attr("class");

    $('#nav').find("div").hasClass(current_selection).show();

});

My HTML
<a href="#" class="link-one">Nav Option One</a>
<div id="nav">
    <div class="nav-link link-one">
        <p>Test Link One</p>
    </div>
</div>

Error I'm getting in the console

Uncaught TypeError: $(...).find(...).hasClass(...).show is not a
  function

A:

hasClass returns boolean value, so you cannot chain hasClass.
You can use
$('#nav').find("div." + current_selection).show();

If current_selection contains multiple classes, the classes will contains spaces and the selector will not work as expected. To make it work, all the spaces need to be replaced by ..
current_selection = $(this).attr("class").replace(/ /g, '.');
$('#nav').find("div." + current_selection).show();

A:

hasClass() returns true or false. You'll want to actually select the appropriate elements:
 $("#nav div." + current_selection).show();

