JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="datas">
    <li class="data-smh1">abc</li>
    <li class="data-smh1">dd</li>
    <li class="data-smh1">cc</li>
    <li class="data-sc33">abc</li>
    <li class="data-sc33">dd</li>
    <li class="data-nn61">abc</li>
    <li class="data-nn61">dd</li>
</ul>

JavaScript

$(document).ready(function(){
    var curr_class = '';
    var ctr = 0;    
    
    $('.datas li').each(function(){
        if (curr_class !== $(this).prop('class')){
            curr_class = $(this).prop('class');
            ctr = 0;
        }
        if (ctr !== 0 ){
            $(this).remove();
        }
        ++ctr;
    });
    
});