Get first and last n items from a nodelist

const slides = document.querySelectorAll("ul li");
const ul = document.querySelector("ul");

const temp = [];
slides.forEach(slide => {
    const clone = slide.cloneNode(true);
    clone.classList.add("red");
    temp.push(clone);
});

temp.slice(0, 2).reverse().forEach(slide => {
    ul.prepend(slide);
});

temp.slice(-2).forEach(slide => {
    ul.appendChild(slide);
});

.red {
  color:red;
}

<ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
</ul>

const firstElement = document.querySelector('ul li:first-child');
console.log('firstElement', firstElement)

const lastElement = document.querySelector('ul li:last-child');
console.log('lastElement', lastElement)

ul li:first-child {
  color:red;
}

ul li:last-child {
  color:green;
}

<ul>
  <li>1</li>
  <li>2</li>
  <li>3</li>
  <li>4</li>
</ul>