Event types

Event types are a shared Chronicle concept. Use the shared documentation for the model, naming rules, generations, and schema evolution flow.

• Event type concept
• Events and event logs
• Event evolution
• TypeScript client setup

In standard and legacy decorator modes, use a @field(Type) instance field and a constructor that assigns it when you want new Event(value). Do not decorate a constructor parameter: the field supplies the runtime schema type, while the constructor makes creation convenient. Name each constructor parameter after the field it assigns; in standard mode a differently named parameter fails schema generation. Keep constructors safe to call without arguments so schema inspection and deserialization can construct the class. See Decorator mode and schema types.

When you configure ChronicleOptions with clientArtifactsProvider, the store uses that catalog for discovery, registration, and schema validation instead of the global default provider.

isRegisteredEvent(store, value) narrows an unknown value to an object only if it is an instance of a decorated, current-generation event type in that store’s discovered catalog. A decorated type that is not in store.eventTypes.all returns false; call it after artifact discovery. This helps distinguish command responses from events without classifying every object as an event.