# DiagramEntity

Import it from `@grafloria/engine`.

```ts
abstract class DiagramEntity
```

**Properties**

| Name | Type | Default | Description |
| --- | --- | --- | --- |
| `id` | `string` |  |  |
| `uuid` | `string` |  |  |
| `version` | `number` | `1` |  |
| `metadata` | `Map<string, any>` |  |  |

**Methods**

- `constructor(id?: string, uuid?: string)`
- `get isDirty(): boolean` — Check if entity has been modified since last render
- `markDirty(reason?: string): void` — Mark entity as dirty (needs re-render)
- `markClean(): void` — Mark entity as clean (rendered)
- `getDirtyReasons(): string[]` — Get reasons why entity is dirty
- `getDirtyTimestamp(): number | null` — Get timestamp when entity was marked dirty
- `beginBatch(): void` — Begin batch update Delays dirty marking until batch ends
- `endBatch(): void` — End batch update Marks dirty once if any changes occurred
- `isBatching(): boolean` — Check if currently in batch mode
- `reportRegisterWrite(property: string, oldValue: unknown, newValue: unknown): void` — REPORT A REGISTER WRITE THE COLLAB REDUCER JUST PERFORMED.
- `on(event: string, handler: Function): () => void` — Subscribe to changes
- `onPropertyChange(property: string, handler: (data: any) => void): () => void` — Subscribe to property changes
- `getChangeLog(): ReadonlyArray<ChangeEntry>` — Get change history
- `clearChangeLog(): void` — Clear change history
- `getLabel(): string | undefined` — CANONICAL label read. `metadata.label` wins; legacy `data['label']` (on subclasses that carry a data bag) is honoured as a fallback so pre-canon documents and third-party writers still surface their labels everywhere — rendering, a11y names, and Mermaid export alike.
- `setLabel(label: string): void` — CANONICAL label write. Writes `metadata.label` (tracked → dirty → repaint) and mirrors into the legacy `data['label']` slot when the entity has a data bag, so any reader still on the old field sees the same value. The mirror is a shadow: metadata is authoritative on every read path.
- `setMetadata(key: string, value: any): void` — Set metadata value
- `getMetadata(key: string): any` — Get metadata value
- `deleteMetadata(key: string): void` — Remove metadata
- `abstract serialize(): SerializedEntity` — Serialize entity to JSON
- `isDisposed(): boolean` — Check if entity has been disposed
- `dispose(): void` — Dispose entity and clean up resources Prevents memory leaks by: - Removing all event listeners - Clearing change log - Clearing metadata - Marking as disposed