JSFiddle - React, Tailwind, and code Playground

HTML

<div id="glorp"></div>

JavaScript

foo = function(bar) {
    var glorp;
    if(typeof bar == 'undefined'){bar = 'baz'}; // there will be other conditions later
    if('baz' == bar) {
        glorp += 'this, ';
        glorp += 'that, ';
        glorp += 'the other';
        return glorp;
    }
}

$('#glorp').append(foo());