JSFiddle - React, Tailwind, and code Playground

HTML

<div id="log">
<a href="#" class="in" id="Sign-up">Sign up</a>
<a href="#" class="in" id="L-in">Login</a>
<a href="#" class="in" id="User">Account</a>
<a href="#" class="in" id="L-out">Logout</a>
</div>

CSS

.in
{
    display: none;
}

JavaScript

$(document).ready(function(){
    var inAccount = 0;
    if (inAccount == 0){
        $("#User").show();
        $("#L-out").show();
    }else{
        $("#Sign-up").show();
        $("#L-in").show();
    }
});