JSFiddle - React, Tailwind, and code Playground

HTML

<div id="spoilerbtn">
  <a> Показать ещё</a>        
</div>
<div class="spoiler" id="spoiler">
    <div>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Reiciendis modi quidem, necessitatibus ipsum adipisci dolorem ratione et maiores similique totam enim aut quasi, officia ut, nihil soluta dolores quos. Expedita.</div>
</div>

CSS

.spoiler{
  display:none;
}
.spoilervis{
  display:block;
}

JavaScript

let count = 1;
        function Spoiler() {
            document.querySelector('#spoiler').classList.toggle('spoiler');
            document.querySelector('#spoiler').classList.toggle('spoilervis');
            const link = document.querySelector('#spoilerbtn a');
            let text;
            if(count){
            		text = 'Скрыть';
                count = 0;
            }else{
                text = 'Показать еще';   
                count = 1;
            }
            link.innerText = text;
            
        }
            document.querySelector('#spoilerbtn').addEventListener('click', Spoiler);