JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#" class="nav-js-trigger">menu</a>
<div class="hidden">Hello</div>

CSS

.hidden {
    display:none;
}

.show-nav {
    background:yellow;
    display:block !important;
}

JavaScript

jQuery(".nav-js-trigger").each(function(){
    this.onclick = function() {
    
        var hasClass;
        hasClass = jQuery(this).next().hasClass( "show-nav" );
        
        jQuery('.show-nav').removeClass('show-nav');
        
        if (hasClass === false) {
            jQuery(this).next().addClass( "show-nav" );
        }
        
    }
});