JSFiddle - React, Tailwind, and code Playground

HTML

<div class="selected-files">Teste 1</div>
<div class="selected-files">Teste 2</div>
<div class="selected-files">Teste 3</div>
<div class="selected-files">Teste 4</div>

JavaScript

var elementos = document.querySelectorAll('.selected-files');
for (var i = 0; i < elementos.length; i++) {
    elementos[i].style.opacity = 1;
    fade(elementos[i], 600);
}

function fade(el, duracao) {
    if ((el.style.opacity -= 40 / duracao) < 0) el.style.display = "none";
    else setTimeout(function () {
        fade(el, duracao);
    }, 40);
};