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

let index = 5;

console.log(`Using an index of ${index} the character returned is ${sentence.at(index)}`);
// Expected output: "Using an index of 5 the character returned is u"

index = -4;

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