# `Kreuzberg.DocumentNode`
[🔗](https://github.com/kreuzberg-dev/kreuzberg/blob/main/lib/kreuzberg/document_structure.ex#L168)

A single node in the document tree.

Each node has a deterministic ID, typed content, optional parent/children references,
and metadata like page number and content layer classification.

## Fields

  * `:id` - Deterministic identifier (hash of content + position)
  * `:node_type` - Node type discriminant (paragraph, heading, list, etc.)
  * `:content` - Node content as a map with type-specific fields
  * `:content_layer` - Content layer classification (body, header, footer, footnote)
  * `:parent` - Parent node index (nil if root node)
  * `:children` - List of child node indices in reading order
  * `:page_number` - Page number where node starts (1-indexed)
  * `:page_number_end` - Page number where node ends (for multi-page elements)
  * `:bbox` - Bounding box coordinates if available
  * `:annotations` - List of inline text annotations

## Examples

    iex> node = %Kreuzberg.DocumentNode{
    ...>   id: "node-1",
    ...>   node_type: "paragraph",
    ...>   content: %{"text" => "Hello world"},
    ...>   page_number: 1
    ...> }
    iex> node.node_type
    "paragraph"

# `node_type`

```elixir
@type node_type() ::
  :title
  | :heading
  | :paragraph
  | :list
  | :list_item
  | :table
  | :image
  | :code
  | :quote
  | :formula
  | :footnote
  | :group
  | :page_break
```

# `t`

```elixir
@type t() :: %Kreuzberg.DocumentNode{
  annotations: [Kreuzberg.DocumentTextAnnotation.t()],
  bbox: Kreuzberg.BoundingBox.t() | nil,
  children: [non_neg_integer()],
  content: map(),
  content_layer: String.t() | nil,
  id: String.t(),
  node_type: String.t(),
  page_number: non_neg_integer() | nil,
  page_number_end: non_neg_integer() | nil,
  parent: non_neg_integer() | nil
}
```

# `from_map`

```elixir
@spec from_map(map()) :: t()
```

Creates a DocumentNode struct from a map.

Converts a plain map (typically from NIF/Rust) into a proper struct,
handling nested content and annotation data.

## Parameters

  * `data` - A map containing node fields

## Returns

A `DocumentNode` struct with properly typed fields.

## Examples

    iex> node_map = %{
    ...>   "id" => "node-1",
    ...>   "node_type" => "paragraph",
    ...>   "content" => %{"text" => "Hello"},
    ...>   "page" => 1
    ...> }
    iex> node = Kreuzberg.DocumentNode.from_map(node_map)
    iex> node.node_type
    "paragraph"

# `has_children?`

```elixir
@spec has_children?(t()) :: boolean()
```

Check if this node has children.

## Parameters

  * `node` - A `DocumentNode` struct

## Returns

Boolean indicating whether the node has child nodes.

## Examples

    iex> node = %Kreuzberg.DocumentNode{children: [1, 2]}
    iex> Kreuzberg.DocumentNode.has_children?(node)
    true

# `readable_type`

```elixir
@spec readable_type(t()) :: String.t()
```

Get node type with readable formatting.

Converts snake_case node types to Title Case for display.

## Parameters

  * `node` - A `DocumentNode` struct

## Returns

A human-readable string representation of the node type.

## Examples

    iex> node = %Kreuzberg.DocumentNode{node_type: "list_item"}
    iex> Kreuzberg.DocumentNode.readable_type(node)
    "List Item"

# `root?`

```elixir
@spec root?(t()) :: boolean()
```

Check if this is a root node (no parent).

## Parameters

  * `node` - A `DocumentNode` struct

## Returns

Boolean indicating whether the node is a root node.

## Examples

    iex> node = %Kreuzberg.DocumentNode{parent: nil}
    iex> Kreuzberg.DocumentNode.root?(node)
    true

# `to_map`

```elixir
@spec to_map(t()) :: map()
```

Converts a DocumentNode struct to a map.

Useful for serialization and passing to external systems.

## Parameters

  * `node` - A `DocumentNode` struct

## Returns

A map with string keys representing all fields.

## Examples

    iex> node = %Kreuzberg.DocumentNode{
    ...>   id: "node-1",
    ...>   node_type: "paragraph",
    ...>   content: %{"text" => "Hello"}
    ...> }
    iex> map = Kreuzberg.DocumentNode.to_map(node)
    iex> map["node_type"]
    "paragraph"

---

*Consult [api-reference.md](api-reference.md) for complete listing*