@ue-too/being / index / StateMachine

Interface: StateMachine<EventPayloadMapping, Context, States, EventOutputMapping>

Defined in: interface.ts:212

Description

This is the interface for the state machine. The interface takes in a few generic parameters.

Generic parameters:

• EventPayloadMapping: A mapping of events to their payloads.
• Context: The context of the state machine. (which can be used by each state to do calculations that would persist across states)
• States: All of the possible states that the state machine can be in. e.g. a string literal union like "IDLE" | "SELECTING" | "PAN" | "ZOOM"
• EventOutputMapping: A mapping of events to their output types. Defaults to void for all events.

You can probably get by using the TemplateStateMachine class. The naming is that an event would "happen" and the state of the state machine would "handle" it.

See

• TemplateStateMachine
• KmtInputStateMachine

Type Parameters

EventPayloadMapping

EventPayloadMapping

Context

Context extends BaseContext

States

States extends string = "IDLE"

EventOutputMapping

EventOutputMapping extends Partial<Record<keyof EventPayloadMapping, unknown>> = DefaultOutputMapping<EventPayloadMapping>

Properties

context?

readonly optional context: Context

Defined in: interface.ts:229

Read-only access to the machine's live context object. Optional so existing StateMachine implementations remain valid; TemplateStateMachine always provides it. Intended for tooling/introspection (e.g. visualizers evaluating guards against the current context) — mutate state through events, not through this reference.

---

currentState

currentState: States | "INITIAL" | "TERMINAL"

Defined in: interface.ts:289

---

possibleStates

possibleStates: States[]

Defined in: interface.ts:258

---

states

states: Record<States, State<EventPayloadMapping, Context, string extends States ? string : States, EventOutputMapping>>

Defined in: interface.ts:242

Methods

happens()

Call Signature

happens<K>(...args): EventResult<States, K extends keyof EventOutputMapping ? EventOutputMapping[K<K>] : void>

Defined in: interface.ts:231

Type Parameters

K

K extends string | number | symbol

Parameters

args

...EventArgs<EventPayloadMapping, K>

Returns

EventResult<States, K extends keyof EventOutputMapping ? EventOutputMapping[K<K>] : void>

Call Signature

happens<K>(...args): EventResult<States, unknown>

Defined in: interface.ts:238

Type Parameters

K

K extends string

Parameters

args

...EventArgs<EventPayloadMapping, K>

Returns

EventResult<States, unknown>

---

onEventResult()?

optional onEventResult(callback): void | () => void

Defined in: interface.ts:283

Subscribe to every event result. Optional so existing StateMachine implementations remain valid; TemplateStateMachine always provides it. Returns a disposer on implementations that support one. Disposing during a dispatch takes effect starting with the next dispatch, not the one in progress — see EventResultCallback for the exact snapshot-iteration semantics.

Parameters

callback

EventResultCallback<EventPayloadMapping, Context, States>

Returns

void | () => void

---

onHappens()

onHappens(callback): void | () => void

Defined in: interface.ts:266

Subscribe to every happens() call, before the state handles it. Returns a disposer on implementations that support one. Disposing during a dispatch takes effect starting with the next dispatch, not the one in progress — see EventResultCallback for the exact snapshot-iteration semantics.

Parameters

callback

(args, context) => void

Returns

void | () => void

---

onStateChange()

onStateChange(callback): void | () => void

Defined in: interface.ts:257

Subscribe to state changes. Returns a disposer on implementations that support one. Disposing during a dispatch takes effect starting with the next dispatch, not the one in progress — see EventResultCallback for the exact snapshot-iteration semantics.

Parameters

callback

StateChangeCallback<States>

Returns

void | () => void

---

reset()

reset(): void

Defined in: interface.ts:286

Returns

void

---

setContext()

setContext(context): void

Defined in: interface.ts:241

Parameters

context

Context

Returns

void

---

start()

start(): void

Defined in: interface.ts:287

Returns

void

---

switchTo()

switchTo(state): void

Defined in: interface.ts:220

Parameters

state

States

Returns

void

---

wrapup()

wrapup(): void

Defined in: interface.ts:288

Returns

void