Actors in XState

Learn all about using actors in XState.

• Introducing actors

  When you run a statechart, it becomes an actor, a running process that can receive events. Often, you’ll need your actor to run other actors.

• Promises

  The most common type of actors you’ll invoke are promise actors. Promise actors allow you to await the result of a promise before deciding what to do next.

• Actions vs. actors

  Sometimes it’s unclear whether you should use an action or an actor. Both appear to do similar things, executing side effects. Let’s break down the differences.

• Callbacks

  Promise actors let you model promises, but not every actor will be a promise. Callback actors give you a flexible API for managing a long-running actor.

• Machines

  Machine actors enable you to create machines that can act as reusable modules across your application. You can pass a machine directly to the invoke src.

• Observables

  Observables are streams of values emitted over time. Observables can be invoked, sending events to the parent machine.

• Parent to child communication

  Invoked actors can send events to their parent using the sendParent and sendBack methods. Child actors can also receive events from the parent.

• Spawning actors

  You can use spawn to run actors. Actors created with spawn are spawning actors, and actors created with invoke are invoking actors.

• Actor cheatsheet

  Get working quickly with actors using our quick reference XState cheatsheet, including spawning, sending, and receiving.