> For AI agents: the complete documentation index is available at https://gultyayev.github.io/ngx-virtual-dnd/llms.txt, the full documentation bundle is available at https://gultyayev.github.io/ngx-virtual-dnd/llms-full.txt.

# Utilities

See [Handling drops](https://gultyayev.github.io/ngx-virtual-dnd/guide/essentials/handling-drops.md) for how to choose between them.

## moveItem

```ts
function moveItem<T>(event: DropEvent, lists: Record<string, WritableSignal<T[]>>): void;
```

Moves the item between (or within) signal-based lists, keyed by droppable ID. Same-list drops are delegated to `reorderItems`. If either droppable ID is missing from `lists`, or the source item does not exist, nothing happens and a warning is logged in dev mode.

## reorderItems

```ts
function reorderItems<T>(event: DropEvent, list: WritableSignal<T[]>): void;
```

Reorders a single signal-based list. Use it for same-list drops only. If the source item does not exist (for example, the list changed during the drag), nothing happens and a warning is logged in dev mode.

## applyMove

```ts
function applyMove<T>(event: DropEvent, lists: Record<string, T[]>): Record<string, T[]>;
```

Immutable version for stores. Returns a shallow copy of `lists` with new arrays for the source and destination. If the source item does not exist, it returns a shallow copy with the original arrays.

## isNoOpDrop

```ts
function isNoOpDrop(event: DropEvent): boolean;
```

`true` when the source and destination droppable and index are equal, meaning the item was dropped where it started.

## insertAt / removeAt

```ts
function insertAt<T>(list: T[], item: T, index: number): T[];
function removeAt<T>(list: T[], index: number): T[];
```

Return new arrays; the input is not modified.