Labels

Labels are strings that can be attached to entities and then used during querying.

Attaching a label to an entity

After spawning an entity, call setEntityLabel(entityId, label):

const id = engine.spawn(...)

engine.setEntityLabel(id, "My Important Label")

Getting a label from an entity

To check which label is attached to an entity, call getEntityLabel(entityId):

const label = engine.getEntityLabel(id)

If no label was attached to the entity, it will return undefined.

Querying result by Label

When querying entities with Query<T>, the results will have a method called getByLabel(label) that can be called to get the first entity in the results that has the label specified attached.

function system(query: Query<[Car]>) {
  const result = query.getByLabel("Toyota")
  if (result) {
    console.log(result[0]) // car component
  }
}