JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
<div>
<div class="publication addyearclasshere">
<div class="publication-date">15/3/2017</div>
</div>

<div class="publication addyearclasshere">
<div class="publication-date">15/3/2016</div>
</div>

</div>

JavaScript

$(".publication-date").each(function(i) {
    var yr = $(this).text().trim().split('/')[2];
    $(this).parent('.publication').addClass(yr);
});