XState 6.0.0-alpha.12

Patch Changes

• 4d9ba1c: Spawning a child with enq.spawn(...) from a transition function now creates and starts the child actor exactly once for the committed transition.

  const machine = createMachine({
    on: {
      spawn: (_, enq) => {
        enq.spawn(childMachine, { registryKey: 'child' });
      }
    }
  });
  

• 6798cb1: serializeMachine(...) and createMachineFromConfig(...) now represent inline functions (guards, actions, transitions, delays, route functions) as { '@code': string, '@lang': 'ts' }. Non-portable values such as actor logic, runtime schemas, class instances, symbols, and bigints are omitted from the serialized JSON.

  import { serializeMachine } from 'xstate';
  
  serializeMachine(machine);
  // inline functions → { '@code': '() => true', '@lang': 'ts' }
  

  Type-only refinements: void and undefined are accepted as type-only schemas, async logic output is inferred from an input-only schema, actions/guards can be typed via schemas, and trigger is correctly typed on spawned actors.