Function nodeAt

nodeAt<L extends IDoublyLinkedList<IDoublyLinkedListNode>>(
instance: L,
index: number,
): undefined | NonNullable<L["head"]>
Retrieves the node at the specified index in a doubly linked list.

Optimizes traversal by starting from head or tail based on index position.
- Time Complexity: O(min(index, n - index)) - traverses from nearest end.
- Space Complexity: O(1)
Type Parameters
- L extends IDoublyLinkedList<IDoublyLinkedListNode>
  The type of the list.
Parameters
- instance: L
  The list instance.
- index: number
  The zero-based index of the node to retrieve.
Returns undefined | NonNullable<L["head"]>
The node at the specified index, or undefined if the index is out of bounds.
- Defined in src/core/doubly-linked-list/list.ts:38