The new array method at() allows us to get access to array indexes using both positive as negative indexes.

This way we don't need to do maths anytime we want to access to the last array element.

const movies = [`Terminator 2`, `Rambo`, `Harry Potter`, `Star Wars`];

const oldWay = movies[movies.length - 1];
console.log(`The last movie is ${oldWay}`); // Star Wars

const newWay = movies.at(-1);
console.log(`The last movie is ${newWay}`); // Star Wars

It's not just for the last element:

console.log(`First movie ${movies.at(0)}`); // Terminator 2

If we pass an index that not exists it will return Undefined.

At this time the array method at() it's not compatible with all the browsers yet so for use it on production you will need a polyfill.

You can find more information at Mozilla MDN