JSFiddle - React, Tailwind, and code Playground

HTML

<p>Ball</p>

    <p>Ball</p>

    <p>Ball</p>

    <p>Boy</p>

    <p>Brain</p>

    <p>Bat</p>

    <p>Bat</p>

CSS

.hidden {
    display: none;
}

JavaScript

var letter = 'B';
    
    var array = [];

    function finish(){
        jQuery('p').each(function(){
            $th = jQuery(this);
            if($th.text().substr(0,1).toUpperCase() == letter) {
                if(jQuery.inArray($th.text(), array) > -1) {
                    $th.addClass('hidden');
                } else {
                     $th.addClass('current-series');
                    array.push($th.text());
                }
            }
       })
    }

finish();