Class: EntityManager
The EntityManager is a foundational class within an Entity-Component-System (ECS) architecture. It's responsible for the full lifecycle and organization of entities and their associated components. This includes operations like creating and destroying entities, as well as adding, removing, querying, and retrieving components linked to those entities. An entity is typically a unique identifier (see EntityId), components hold data (see ComponentData), and component types are identified by name (see ComponentTypeName).
Source: ecs/EntityManager.js, line 14
Constructor
new EntityManager()
Creates a new instance of the EntityManager. This initializes the internal structures required to store, track, and manage entities and their components effectively.
Source: ecs/EntityManager.js, line 14
Methods
addComponent(entityId, componentTypeName, data)
Adds a component of a specific type with the given data to an entity. If the entity already possesses a component of the same type, the existing component's data will be overwritten with the new data.
Parameters:
| Name | Type | Description |
|---|---|---|
entityId | EntityId | The unique identifier of the entity to which the component will be added. |
componentTypeName | ComponentTypeName | The string name identifying the type of component (e.g., "Position", "Velocity"). |
data | [ComponentData](global.html#ComponentData) | The actual data or state for this component instance. |
Returns: [ComponentData](global.html#ComponentData) | undefined The component data that was added, or undefined if the specified entityId does not correspond to an existing entity.
Source: ecs/EntityManager.js, line 105
createEntity()
Generates a new, unique entity and returns its identifier. This new entity initially has no components.
Returns: EntityId The unique identifier (EntityId) for the newly created entity.
Source: ecs/EntityManager.js, line 55
destroyEntity(entityId)
Removes an entity and all components associated with it from the manager. After this operation, the entity ID is no longer considered alive.
Parameters:
| Name | Type | Description |
|---|---|---|
entityId | EntityId | The unique identifier of the entity to be destroyed. |
Source: ecs/EntityManager.js, line 67
getAllComponents(entityId)
Retrieves a collection of all components currently associated with a specific entity.
Parameters:
| Name | Type | Description |
|---|---|---|
entityId | EntityId | The unique identifier of the entity to query. |
Returns: Map<ComponentTypeName, [ComponentData](global.html#ComponentData)> | undefined A Map where keys are ComponentTypeName strings and values are the corresponding ComponentData objects for the entity. Returns undefined if the entity is not found.
Source: ecs/EntityManager.js, line 192
getComponent(entityId, componentTypeName)
Retrieves a specific component instance from an entity, identified by its type name.
Parameters:
| Name | Type | Description |
|---|---|---|
entityId | EntityId | The unique identifier of the entity. |
componentTypeName | ComponentTypeName | The string name identifying the type of component to retrieve. |
Returns: [ComponentData](global.html#ComponentData) | undefined The data for the specified component if found on the entity; otherwise, undefined.
Source: ecs/EntityManager.js, line 171
getEntitiesWithComponents(componentTypeNames)
Finds and returns the IDs of all entities that possess all of the component types specified in the input array. This is useful for systems that operate on entities with a specific set of capabilities.
Parameters:
| Name | Type | Description |
|---|---|---|
componentTypeNames | Array<ComponentTypeName> | An array of string names, each identifying a required component type. |
Returns: Array<EntityId> An array containing the EntityIds of all entities that match the criteria. If no component types are specified in the input array or if no entities possess all the listed components, an empty array is returned.
Source: ecs/EntityManager.js, line 202
hasComponent(entityId, componentTypeName)
Checks whether a given entity currently has a component of a specific type.
Parameters:
| Name | Type | Description |
|---|---|---|
entityId | EntityId | The unique identifier of the entity. |
componentTypeName | ComponentTypeName | The string name identifying the type of component to check for. |
Returns: booleantrue if the entity possesses the specified component type, false otherwise (including if the entity itself does not exist).
Source: ecs/EntityManager.js, line 182
isEntityAlive(entityId)
Determines if an entity with the given ID currently exists and is managed (i.e., has not been destroyed).
Parameters:
| Name | Type | Description |
|---|---|---|
entityId | EntityId | The unique identifier of the entity whose existence is to be checked. |
Returns: booleantrue if an entity with the specified entityId exists within the manager, false otherwise.
Source: ecs/EntityManager.js, line 94
removeComponent(entityId, componentTypeName)
Removes a specific component type from an entity.
Parameters:
| Name | Type | Description |
|---|---|---|
entityId | EntityId | The unique identifier of the entity from which the component will be removed. |
componentTypeName | ComponentTypeName | The string name identifying the type of component to remove. |
Returns: booleantrue if the component was successfully found and removed. false if the entity doesn't exist or if the entity did not possess a component of the specified type.
Source: ecs/EntityManager.js, line 140