JSFiddle - React, Tailwind, and code Playground
HTML
<textarea id="ta">I want to tag #thisperson</textarea>
<div>
<ul id="choices">
<li>PersonA</li>
<li>PersonB</li>
<li>PersonC</li>
</ul>
</div>
JavaScript
$(function(){
$("#choices li").click(function(){
var name = $(this).text();
$("#ta").val($("#ta").val().replace("#thisperson", name));
})
})