JSFiddle - React, Tailwind, and code Playground
HTML
<div id="result">
</div>JavaScript
var messages = [ 'fail' ];
var optional = true;
var result = optional || messages.length === 0;
var result = optional || ! messages.length;
console.log( ! optional );
console.log( messages.length );
var output = result ? "passes" : "fails";
$('#result').text( output );