Dispatching events

Dispatch is how state changes. You address a machine by its imported definition and send a typed event — no magic strings.

Typed, no magic strings

dispatch(CartMachine, { type: 'ADD_ITEM', productId: id })

The event is checked against the machine’s declared union (EventOf<typeof CartMachine>). A wrong type or a missing field is a compile error.

Where dispatch happens

• In a template handler — on:click={() => cart.send({ type: 'ADD_ITEM', productId: id })} (the read instance’s send).
• In an API route — dispatch(Machine, event) from the handler’s helpers.

Both run server-side today.

Cross-machine fan-out

A dispatch records every touched machine. Subscribers (subscribes/emits) react, their machines are persisted, and on a live route the changes fan out to connected sessions.

How patches come back

The dispatch triggers a recompute; the response is a patch list targeting only the changed slots.

Client dispatch

From a client island, dispatch to a server machine over /__events:

dispatch(CartMachine, { type: 'ADD_ITEM', productId: id })

Phase 3b

Client-to-server dispatch is partly behind the in-progress client plane (it needs the import-stubbing that strips a server machine’s body from the browser bundle while keeping its name and event types). Islands using only portable client machines work today.