Glossary
Terms used throughout the XState documentation.
Actor: A running process that receives events and produces snapshots.
Actor logic: The rules used by an actor to process events.
Action: An effect scheduled by a transition.
Context: Data stored in a state machine snapshot.
Event: A value sent to an actor. Events have a type.
Guard: A condition that chooses whether a transition can run.
Input: Data provided when an actor is created.
Invoked actor: A child actor whose lifecycle belongs to a state.
Output: Final data produced when an actor completes.
Snapshot: An actor's observable state at one point in time.
Spawned actor: A child actor created during a transition and managed by its parent.
State: A named mode in a state machine.
State machine: A model with a finite set of states and transitions.
Statechart: A state machine with features such as nested, parallel and history states.
Transition: A response to an event that may change state, context or run effects.