JSFiddle - React, Tailwind, and code Playground

HTML

<button id="botao" data-order="day-0">Clique</button>

JavaScript

$('#botao').on('click', function () {
    var valor = $(this).data('order').split('-')[1];
    valor++;
    $(this).data('order', 'day-' + valor);
    console.log( $(this).data('order') );
    console.log( $(this).attr('data-order') );
});