# XState 6.0.0-alpha.4

- Product: XState (https://whatsnew.fyi/product/xstate)
- Vendor: Stately
- Date: 2026-06-23
- Version: 6.0.0-alpha.4
- Original notes: https://github.com/statelyai/xstate/releases/tag/xstate%406.0.0-alpha.4
- Permalink: https://whatsnew.fyi/product/xstate/releases/6.0.0-alpha.4
- Labels: Pre-release

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **changed** — Actor logic now returns effects from both regular and initial transitions, with transition(...) and initialTransition(...) returning [snapshot, effects] tuples
- **added** — Add schemas.children for explicitly typing child actor refs by child ID with declared child refs type, child snapshots, and invoke configs
- **added** — Add isBuiltInExecutableAction(...) to narrow executable effects to XState's built-in effect union for declarative inspection
- **changed** — Built-in executable effects now expose stable named metadata fields accessible via effect.type including @xstate.start, @xstate.sendTo, @xstate.raise, and @xstate.stop
- **changed** — fromStore(...) effects now run after the actor snapshot is committed so effect callbacks read the updated snapshot from enqueue.getSnapshot()

###### Major Changes

-   c3f7a9d: Actor logic now returns effects from both regular and initial transitions.

    Hand-written actor logic should return `[snapshot, effects]` from `transition(...)` and provide `initialTransition(...)` for creating the initial `[snapshot, effects]` tuple. `getInitialSnapshot(...)` remains available for snapshot-only reads.

    ```ts
    const logic = {
      transition: (snapshot, event) => [snapshot, []],
      initialTransition: (input, _scope) => [
        {
          status: 'active',
          output: undefined,
          error: undefined,
          input
        },
        []
      ],
      getInitialSnapshot: (scope, input) =>
        logic.initialTransition(input, scope)[0]
    };
    ```

    `transition(...)` and `initialTransition(...)` continue to return `[snapshot, actions]` for machine logic.

    `fromStore(...)` effects now run after the actor snapshot is committed, so effect callbacks read the updated snapshot from `enqueue.getSnapshot()`.

-   309b106: Add `schemas.children` for explicitly typing child actor refs by child ID. Declared child refs type `children.someId`, child snapshots, and invoke configs so `invoke: { id: 'someId', src }` must match the declared child actor contract.

-   fa2bbf0: Built-in executable effects returned from `transition(...)` and `initialTransition(...)` are now easier to inspect declaratively.

    Use `isBuiltInExecutableAction(effect)` to narrow an executable effect to XState's built-in effect union, then switch on `effect.type` to access stable, named metadata fields:

    ```ts
    const [snapshot, effects] = initialTransition(machine);

    for (const effect of effects) {
      if (!isBuiltInExecutableAction(effect)) {
        continue;
      }

      switch (effect.type) {
        case '@xstate.start':
          effect.id;
          effect.logic;
          effect.src;
          effect.input;
          break;

        case '@xstate.sendTo':
          effect.target;
          effect.event;
          effect.delay;
          break;

        case '@xstate.raise':
          effect.event;
          effect.delay;
          break;
      }
    }
    ```

    The built-in stop effect is now exposed as `@xstate.stop`, matching `@xstate.start`.