JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <button class="up">Up</button> 
    <button class="down">Down</button> 
    <div>Rank = <span class="rank">0</span></div>
</div>
<div>
    <button class="up">Up</button> 
    <button class="down">Down</button> 
    <div>Rank = <span class="rank">0</span></div>
</div>
<div>
    <button class="up">Up</button> 
    <button class="down">Down</button> 
    <div>Rank = <span class="rank">0</span></div>
</div>

JavaScript

$('.up').click(function(){   
     var rank = $(this).parent().find('.rank');
     var val = Number(rank.text());
     rank.text(val + 1);
});

$('.down').click(function(){
     var rank = $(this).parent().find('.rank');
     var val = Number(rank.text());
     rank.text(val - 1);
});