Array.prototype.at()

const array1 = [5, 12, 8, 130, 44];

let index = 2;

console.log(`An index of ${index} returns ${array1.at(index)}`);
// Expected output: "An index of 2 returns 8"

index = -2;

console.log(`An index of ${index} returns ${array1.at(index)}`);
// Expected output: "An index of -2 returns 130"

at(index)

//     
const cart = ["", "", ""];

//      
function returnLast(arr) {
  return arr.at(-1);
}

// 'cart'    
const item1 = returnLast(cart);
console.log(item1); // ''

// 'cart'  
cart.push("");
const item2 = returnLast(cart);
console.log(item2); // ''

//     
const colors = ["", "", ""];

// length  
const lengthWay = colors[colors.length - 2];
console.log(lengthWay); // ''

// slice()  .    
const sliceWay = colors.slice(-2, -1);
console.log(sliceWay[0]); // ''

// at()  
const atWay = colors.at(-2);
console.log(atWay); // ''

const arrayLike = {
  length: 2,
  0: "a",
  1: "b",
  2: "c", // length 2 at()   .
};
console.log(Array.prototype.at.call(arrayLike, 0)); // "a"
console.log(Array.prototype.at.call(arrayLike, 2)); // undefined