String.prototype.at()

const sentence = "The quick brown fox jumps over the lazy dog.";

let index = 5;

console.log(`An index of ${index} returns the character ${sentence.at(index)}`);
// Expected output: "An index of 5 returns the character u"

index = -4;

console.log(`An index of ${index} returns the character ${sentence.at(index)}`);
// Expected output: "An index of -4 returns the character d"

at(index)

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

let invoiceRef = "myinvoice01";

console.log(returnLast(invoiceRef)); // '1'

invoiceRef = "myinvoice02";

console.log(returnLast(invoiceRef)); // '2'

const myString = "Every green bus drives fast.";

// length  charAt()  
const lengthWay = myString.charAt(myString.length - 2);
console.log(lengthWay); // 't'

// slice()  
const sliceWay = myString.slice(-2, -1);
console.log(sliceWay); // 't'

// at()  
const atWay = myString.at(-2);
console.log(atWay); // 't'