JSFiddle - React, Tailwind, and code Playground
HTML
<ul>
<li class="fe footer_no_link"><a class="email" id="contact-mail" href="#"></a></li>
</ul>
JavaScript
var m;
m='in';
m+='f';
m+='o@sit';
m+='e.co';
m+='m';
$ele = document.getElementById('contact-mail');
$ele.href = 'mailto:'+m;
$ele.innerHTML = m;