Class: Entity

Stable handle for a single ECS entity. scene.GetEntity(id) always returns the same instance for a given id, so reference equality (===) is meaningful.

The handle owns no game state — all state lives in components keyed by id in the scene's ComponentRegistry. The methods below are convenience wrappers (name / parent / tag / activation / event emit) so game code doesn't repeatedly fetch HierarchyComponent, NameComponent, etc. for the common operations.

Implements

• IEntity

Constructors

Constructor

new Entity(entityId, parentScene): Entity;

Parameters

Parameter	Type
entityId	number
parentScene	Scene

Returns

Entity

Accessors

transform

Get Signature

get transform(): TransformComponent;

---------- Transform shortcuts ----------

Both return the live component, so writes to its fields still go through the auto-dirty setters: this.entity.transform.x += 5 * dt; // local; TransformSystem composes world this.entity.worldTransform.x = 100; // world override; TransformSystem reverse- composes local on the next tick Throws if the component is missing. Every Scene.CreateEntity has both.

Returns

TransformComponent

---

worldTransform

Get Signature

get worldTransform(): WorldTransformComponent;

Returns

WorldTransformComponent

Methods

AddChild()

AddChild(child): void;

Parameters

Parameter	Type
child	Entity

Returns

void

---

AddComponent()

AddComponent<Component, Args>(type, ...args): Component;

Type Parameters

Type Parameter
Component
Args extends unknown[]

Parameters

Parameter	Type
type	ComponentClass<Component, Args>
...args	Args

Returns

Component

Implementation of

IEntity.AddComponent

---

AddScript()

AddScript<T, Args>(type, ...args): T;

Convenience for attaching a Script. Same as AddComponent but type-narrowed to Script subclasses. The script must have been registered with ComponentRegistry.RegisterScript.

Type Parameters

Type Parameter
T extends Script
Args extends unknown[]

Parameters

Parameter	Type
type	ComponentClass<T, Args>
...args	Args

Returns

T

---

AddTag()

AddTag(tag): void;

Add a tag (no-op if already present). Auto-adds TagComponent if absent.

Parameters

Parameter	Type
tag	string

Returns

void

---

ClearListeners()

ClearListeners(): void;

Drop every listener. Called by Scene.DestroyEntity after firing the 'destroyed' event.

Returns

void

---

Destroy()

Destroy(): void;

Destroy this entity and every descendant. Equivalent to scene.DestroyEntity(this).

Returns

void

---

emit()

emit<T>(name, payload?): void;

Synchronously dispatch name with payload to all subscribed listeners.

Type Parameters

Type Parameter	Default type
T	unknown

Parameters

Parameter	Type
name	string
payload?	T

Returns

void

---

FindAncestor()

FindAncestor(name): Entity | null;

Walk up to a matching ancestor by name. Returns this entity if its own name matches.

Parameters

Parameter	Type
name	string

Returns

Entity | null

---

FindChild()

FindChild(nameOrPath): Entity | null;

Find a descendant by NameComponent.name. Depth-first; supports forward-slash paths ('Background/Tower/Top'). Returns null if no match.

Parameters

Parameter	Type
nameOrPath	string

Returns

Entity | null

---

GetChildAt()

GetChildAt(index): Entity | null;

Direct child at index, or null if out of range.

Parameters

Parameter	Type
index	number

Returns

Entity | null

---

GetChildCount()

GetChildCount(): number;

Number of direct children.

Returns

number

---

GetChildren()

GetChildren(): Entity[];

Snapshot of direct children. Mutating the returned array does NOT affect the hierarchy.

Returns

Entity[]

---

GetComponent()

GetComponent<Component>(type): Component;

Type Parameters

Type Parameter
Component

Parameters

Parameter	Type
type	ComponentClass<Component>

Returns

Component

Implementation of

IEntity.GetComponent

---

GetId()

GetId(): number;

Returns

number

Implementation of

IEntity.GetId

---

GetName()

GetName(): string;

Read the entity's name from NameComponent. Returns '' if no NameComponent is attached.

Returns

string

---

GetParent()

GetParent(): Entity | null;

Returns the parent entity, or null if this is a scene root.

Returns

Entity | null

---

GetParentScene()

GetParentScene(): Scene;

Returns

Scene

Implementation of

IEntity.GetParentScene

---

GetTags()

GetTags(): string[];

Snapshot of all tags.

Returns

string[]

---

HasComponent()

HasComponent<Component>(type): boolean;

Type Parameters

Type Parameter
Component

Parameters

Parameter	Type
type	ComponentClass<Component>

Returns

boolean

Implementation of

IEntity.HasComponent

---

HasListeners()

HasListeners(name): boolean;

True if at least one listener is attached for the event name.

Parameters

Parameter	Type
name	string

Returns

boolean

---

HasTag()

HasTag(tag): boolean;

Parameters

Parameter	Type
tag	string

Returns

boolean

---

IsActive()

IsActive(): boolean;

Local active state — does this entity participate in updates/render IF its ancestors are also active? Mirrors Unity's GameObject.activeSelf.

Returns

boolean

---

IsActiveInHierarchy()

IsActiveInHierarchy(): boolean;

Effective active state in the scene graph — true iff this entity AND every ancestor are active. Updated on SetActive / reparent and by ActiveSystem; mirrors Unity's activeInHierarchy.

Returns

boolean

---

IsAncestorOf()

IsAncestorOf(descendant): boolean;

Is this entity an ancestor of descendant?

Parameters

Parameter	Type
descendant	Entity

Returns

boolean

---

off()

off<T>(
   name, 
   cb?, 
   context?
): void;

Remove listeners for an event name.

• off(name) removes every listener for name
• off(name, cb) removes every entry whose callback equals cb
• off(name, cb, ctx) removes only entries whose (cb, context) pair matches

Type Parameters

Type Parameter	Default type
T	unknown

Parameters

Parameter	Type
name	string
cb?	EntityEventHandler<T>
context?	object

Returns

void

---

on()

on<T>(
   name, 
   cb, 
   context?
): EntityEventUnsubscribe;

Subscribe to an event. Returns an unsubscribe function for cleanup.

Type Parameters

Type Parameter	Default type
T	unknown

Parameters

Parameter	Type
name	string
cb	EntityEventHandler<T>
context?	object

Returns

EntityEventUnsubscribe

---

once()

once<T>(
   name, 
   cb, 
   context?
): EntityEventUnsubscribe;

Subscribe to an event one time — the listener removes itself after the first fire.

Type Parameters

Type Parameter	Default type
T	unknown

Parameters

Parameter	Type
name	string
cb	EntityEventHandler<T>
context?	object

Returns

EntityEventUnsubscribe

---

RemoveComponent()

RemoveComponent<Component>(type): void;

Type Parameters

Type Parameter
Component

Parameters

Parameter	Type
type	ComponentClass<Component>

Returns

void

Implementation of

IEntity.RemoveComponent

---

RemoveTag()

RemoveTag(tag): void;

Remove a tag (no-op if absent).

Parameters

Parameter	Type
tag	string

Returns

void

---

SetActive()

SetActive(active): void;

Toggle local active state; the subtree's activeInHierarchy follows immediately.

Parameters

Parameter	Type
active	boolean

Returns

void

---

SetName()

SetName(name): void;

Set the entity's name on NameComponent (adds the component if absent).

Parameters

Parameter	Type
name	string

Returns

void

---

SetParent()

SetParent(parent): void;

Reparent this entity. Pass null to detach from any parent (make a scene root).

Parameters

Parameter	Type
parent	Entity | null

Returns

void

---

TryGetComponent()

TryGetComponent<Component>(type): Component | undefined;

Type Parameters

Type Parameter
Component

Parameters

Parameter	Type
type	ComponentClass<Component>

Returns

Component | undefined

Implementation of

IEntity.TryGetComponent