JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/ui-lightness/jquery-ui.css">

JavaScript

var a = "check";

function some() {
    return "value";
}

var b;

if( a=="check"  && b,b = some() ) {
    alert('worked');
}