at 
Retrieves elements from an array at the specified indices.
This function supports negative indices, which count from the end of the array.
Signature 
typescript
function at<T>(arr: T[], indices: number[]): Array<T | undefined>;Parameters 
- arr(- T[]): The array to retrieve elements from.
- indices(- number[]): An array of indices specifying the positions of elements to retrieve.
Returns 
(Array<T | undefined>): A new array containing the elements at the specified indices.
Examples 
typescript
import { at } from 'es-toolkit/array';
const numbers = [10, 20, 30, 40, 50];
const result = at(numbers, [1, 3, 4]);
console.log(result); // [20, 40, 50]
