JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="search" />

<ul id="workflow_books">    
<li>
    <h6 class="custom"> Custom Books</h6>

    <ul>
        <li class="custom-books">
            <a>Don't see your book in our list? Add it yourself!</a>
        </li>
    </ul>
</li>

<li>
    <h6>devi</h6>

    <ul>
        <li>
            <a>Academic Book One</a>
        </li>

        <li>
            <a>Academic Book Two</a>
        </li>
    </ul>
</li>

<li>        
    <h6>Botany</h6>

    <ul>
        <li>
            <a>Botany Book One</a>
        </li>

        <li>
            <a>Botany Book Two</a>
        </li>
    </ul>
</li>
</ul>

JavaScript

var $products = $('#workflow_books li ul:not(:first)');
$("#search").keyup(function() {
    var val = this.value.trim();
    if (!val) $('li:hidden', '#workflow_books').show();
    else {
        $('li:hidden', $products).show();
        $('li', $products).filter(function() {
            var re = new RegExp(val, 'ig');
            return !re.test($('a', this).text());
        }).hide();
        $products.each(function() {
            if ($('li:visible', this).length == 0) $(this).parent('li').hide();
            else $(this).parent('li').show();
        });
    }
});