const xx = [" 4", "9", "16"," 4", "9", "16"," 4", "9", "16"]
<ul> {(<li> {[...new Set(xx)]} </li>)} </ul>const xx = [" 4", "9", "16"," 4", "9", "16"," 4", "9", "16"]
Here, this would work fine
const xx = [" 4", "9", "16"," 4", "9", "16"," 4", "9", "16"];
const set = [...new Set(xx)];
let html = '';
set.forEach(el => {
html += `<li>${el}</li>`;
});
document.querySelector("#list").insertAdjacentHTML('afterbegin', html);<ul id="list"></ul>You could also do the same with the array methods
const xx = [" 4", "9", "16"," 4", "9", "16"," 4", "9", "16"];
const html = [...new Set(xx)].map(el => `<li>${el}</li>`).join('');
document.querySelector("#list").insertAdjacentHTML('afterbegin', html);<ul id="list"></ul>