Packages > @fluidframework/tree > TreeNodeApi
TreeNodeApi Interface
Provides various functions for analyzing TreeNode s.
Signature
export interface TreeNodeApi
Properties
| Property | Modifiers | Type | Description |
|---|---|---|---|
| status |
readonly
|
(node: TreeNode) => TreeStatus | Returns the TreeStatus of the given node. |
Methods
| Method | Return Type | Description |
|---|---|---|
| is(value, schema) | value is NodeFromSchema<TSchema> | Narrow the type of the given value if it satisfies the given schema. |
| key(node) | string | number | The key of the given node under its parent. |
| on(node, eventName, listener) | () => void | Register an event listener on the given node. |
| parent(node) | TreeNode | undefined | Return the node under which this node resides in the tree (or undefined if this is a root node of the tree). |
| schema(node) | TreeNodeSchema<string, NodeKind, unknown, T> | The schema information for this node. |
| shortId(node) | number | string | undefined | Returns the identifier of the given node in the most compressed form possible. |
Property Details
status
Returns the TreeStatus of the given node.
Signature
readonly status: (node: TreeNode) => TreeStatus;
Method Details
is
Narrow the type of the given value if it satisfies the given schema.
Signature
is<TSchema extends TreeNodeSchema>(value: unknown, schema: TSchema): value is NodeFromSchema<TSchema>;
Type Parameters
| Parameter | Constraint | Description |
|---|---|---|
| TSchema | TreeNodeSchema |
Example
if (node.is(myNode, point)) {
const y = myNode.y; // `myNode` is now known to satisfy the `point` schema and therefore has a `y` coordinate.
}
Parameters
| Parameter | Type | Description |
|---|---|---|
| value | unknown | |
| schema | TSchema |
Returns
Return type: value is NodeFromSchema <TSchema>
key
The key of the given node under its parent.
Signature
key(node: TreeNode): string | number;
Remarks
If node is an element in a TreeArrayNode
, this returns the index of node in the array node (a number). Otherwise, this returns the key of the field that it is under (a string).
Parameters
| Parameter | Type | Description |
|---|---|---|
| node | TreeNode |
Returns
Return type: string | number
on
Register an event listener on the given node.
Signature
on<K extends keyof TreeChangeEvents>(node: TreeNode, eventName: K, listener: TreeChangeEvents[K]): () => void;
Type Parameters
| Parameter | Constraint | Description |
|---|---|---|
| K | keyof TreeChangeEvents |
Parameters
| Parameter | Type | Description |
|---|---|---|
| node | TreeNode | The node whose events should be subscribed to. |
| eventName | K | Which event to subscribe to. |
| listener | TreeChangeEvents[K] | The callback to trigger for the event. The tree can be read during the callback, but it is invalid to modify the tree during this callback. |
Returns
A callback function which will deregister the event. This callback should be called only once.
Return type: () => void
parent
Return the node under which this node resides in the tree (or undefined if this is a root node of the tree).
Signature
parent(node: TreeNode): TreeNode | undefined;
Parameters
| Parameter | Type | Description |
|---|---|---|
| node | TreeNode |
Returns
Return type: TreeNode | undefined
schema
The schema information for this node.
Signature
schema<T extends TreeNode | TreeLeafValue>(node: T): TreeNodeSchema<string, NodeKind, unknown, T>;
Type Parameters
| Parameter | Constraint | Description |
|---|---|---|
| T | TreeNode | TreeLeafValue |
Parameters
| Parameter | Type | Description |
|---|---|---|
| node | T |
Returns
Return type: TreeNodeSchema <string, NodeKind , unknown, T>
shortId
Returns the identifier of the given node in the most compressed form possible.
Signature
shortId(node: TreeNode): number | string | undefined;
Remarks
If the node’s identifier is a valid StableNodeKey, then this will return a unique process-local integer corresponding to that identifier. If the node’s identifier is any other string, then this will return that string. If the node has no identifier (that is, it has no field of an identifier
field kind), then this returns undefined.
Parameters
| Parameter | Type | Description |
|---|---|---|
| node | TreeNode |
Returns
Return type: number | string | undefined