A toast appears and immediately fadeout, and finally removed

hidingtoast.html

<style>
  @keyframes fadeout {
      from { opacity:1; }
      to { opacity:0; }
  }
  .toast {
      position:fixed; left:0; bottom:0; padding:10px;
      font-size:50px; color:red; font-weight:900;
      animation: fadeout 1s ease-in forwards;
  }
</style>

<script>
function showToast() {
    const el = Object.assign(document.createElement("div"), {
        classList: "toast",
        textContent: "토스트"
    });
    document.body.append(el);
    setTimeout(() => el.remove(), 1000);
}
showToast();
</script>