JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <h4>Filter by Area</h4>             
    <ul id="arealist">
        <li><input type ="checkbox" id="area1" name="area1" value="1" />All</li>
        <li><input type ="checkbox" id="area2" name="area2" value="2" />some</li>
        <li><input type ="checkbox" id="area3" name="area3" value="3" />heavy</li>
        <li><input type ="checkbox" id="area4" name="area4" value="4" />more</li>
        <li><input type ="checkbox" id="area5" name="area5" value="5" />none</li>
    </ul>
</div>

JavaScript

$(function(){
    var areaname=2;
    $('#area'+areaname).prop('checked',true);
});