# PropertyPanelService

Import it from `@grafloria/angular`.

Core service for managing property schemas and property values. Acts as bridge between property panel UI and diagram engine.

```ts
@Injectable({ providedIn: 'root' })
export class PropertyPanelService
```

**Properties**

| Name | Type | Default | Description |
| --- | --- | --- | --- |
| `propertyChanged$` |  |  | Observable that emits when any property changes. Can be filtered by node ID or property key. |

**Methods**

- `registerSchema(nodeType: string, schema: PropertySchema): void` — Register a property schema for a node type.
- `registerSchemaFromJSON(nodeType: string, schemaJson: string): void` — Register schema from JSON string. Enables loading schemas from database or config files.
- `extendSchema( nodeType: string, parentType: string, overrides: Partial<PropertySchema> ): void` — Extend an existing schema to create a specialized type. Child inherits all parent properties and can override or add new ones.
- `getSchema(nodeType: string): PropertySchema | null` — Get property schema for a node type. Returns fully resolved schema (including inherited properties).
- `hasSchema(nodeType: string): boolean` — Check if schema is registered for node type.
- `getAllTypes(): string[]` — Get list of all registered node types.
- `unregisterSchema(nodeType: string): boolean` — Unregister the schema for a node type. Since {@link registerSchema} rejects duplicates, this is the only way to
replace a schema (e.g. hot-reloading schemas from a config source).
- `clearSchemas(): void` — Remove all registered schemas. Useful when tearing down a diagram context or isolating test state.
- `getPropertyValue(node: PropertyDiagramNode, propertyKey: string): any` — Get property value from a node. Supports nested property paths (e.g., 'style.fill.color').
- `setPropertyValue(node: PropertyDiagramNode, propertyKey: string, value: any): any` — Set property value on a node. Validates value against schema before setting.
- `setPropertyValues( nodes: PropertyDiagramNode[], propertyKey: string, value: any ): string[]` — Set property value on multiple nodes simultaneously. Validates once and applies to all nodes. Rolls back all changes if any validation fails.
- `validateProperty(value: any, property: PropertyDefinition): ValidationResult` — Validate a property value against its definition.
- `isPropertyVisible(node: PropertyDiagramNode, property: PropertyDefinition): boolean` — Check if property is visible based on condition. Evaluates condition expression against current node properties.
- `applyDefaults(node: PropertyDiagramNode, schema: PropertySchema): void` — Apply default values from schema to node. Only sets properties that are currently undefined.
- `getPropertyGroups(schema: PropertySchema): Map<string, PropertyDefinition[]>` — Get properties organized by groups. Properties without group go to 'General' group.
- `getPropertyChangesForNode(nodeId: string): Observable<PropertyChangeEvent>` — Filter property change events by node ID.
- `getPropertyChangesForKey(propertyKey: string): Observable<PropertyChangeEvent>` — Filter property change events by property key.