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@ue-too/being / index / TemplateState

抽象 類別: TemplateState<EventPayloadMapping, Context, States, EventOutputMapping> ​

定義於: interface.ts:973

Abstract base class for state machine states.

備註 ​

This abstract class provides the foundation for implementing individual states in a state machine. Each state defines how it responds to events through the eventReactions object.

Key Concepts ​

  • Event Reactions: Define handlers for events this state cares about. Unhandled events are ignored.
  • Guards: Conditional logic that determines which state to transition to based on context
  • Lifecycle Hooks: uponEnter and beforeExit callbacks for state transition side effects
  • Selective Handling: Only define reactions for events relevant to this state

Implementation Pattern ​

  1. Extend this class for each state in your state machine
  2. Implement the eventReactions property with handlers for relevant events
  3. Optionally override uponEnter and beforeExit for lifecycle logic
  4. Optionally define guards and eventGuards for conditional transitions

Examples ​

Simple state implementation

typescript
class IdleState extends TemplateState<MyEvents, MyContext, MyStates> {
  eventReactions = {
    start: {
      action: (context, event) => {
        console.log('Starting...');
        context.startTime = Date.now();
      },
      defaultTargetState: "ACTIVE"
    },
    reset: {
      action: (context, event) => {
        context.counter = 0;
      }
      // No state transition - stays in IDLE
    }
  };

  uponEnter(context, stateMachine, fromState) {
    console.log(`Entered IDLE from ${fromState}`);
  }
}

State with guards for conditional transitions

typescript
class PaymentState extends TemplateState<Events, VendingContext, States> {
  guards = {
    hasEnoughMoney: (context) => context.balance >= context.itemPrice,
    needsChange: (context) => context.balance > context.itemPrice
  };

  eventReactions = {
    selectItem: {
      action: (context, event) => {
        context.selectedItem = event.itemId;
        context.itemPrice = getPrice(event.itemId);
      },
      defaultTargetState: "IDLE" // Fallback if no guard matches
    }
  };

  eventGuards = {
    selectItem: [
      { guard: 'hasEnoughMoney', target: 'DISPENSING' },
      // If hasEnoughMoney is false, uses defaultTargetState (IDLE)
    ]
  };
}

參閱 ​

Extended by ​

型別參數 ​

EventPayloadMapping ​

EventPayloadMapping

Object mapping event names to their payload types

Context ​

Context extends BaseContext

Context type shared across all states

States ​

States extends string = "IDLE"

Union of all possible state names (string literals)

EventOutputMapping ​

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

Optional mapping of events to their output types

實作 ​

  • State<EventPayloadMapping, Context, States, EventOutputMapping>

建構函式 ​

建構函式 ​

new TemplateState<EventPayloadMapping, Context, States, EventOutputMapping>(): TemplateState<EventPayloadMapping, Context, States, EventOutputMapping>

回傳 ​

TemplateState<EventPayloadMapping, Context, States, EventOutputMapping>

屬性 ​

_defer ​

protected _defer: Defer<Context, EventPayloadMapping, States, EventOutputMapping> | undefined = undefined

定義於: interface.ts:1007

_delay ​

protected _delay: Delay<Context, EventPayloadMapping, States, EventOutputMapping> | undefined = undefined

定義於: interface.ts:1003

_eventGuards ​

protected _eventGuards: Partial<EventGuards<EventPayloadMapping, States, Context, Guard<Context>>>

定義於: interface.ts:993

_eventPreconditions ​

protected _eventPreconditions: Partial<EventPreconditions<EventPayloadMapping, Context, Guard<Context>>>

定義於: interface.ts:998

_eventReactions ​

protected _eventReactions: EventReactions<EventPayloadMapping, Context, States, EventOutputMapping>

定義於: interface.ts:981

_guards ​

protected _guards: Guard<Context>

定義於: interface.ts:992

存取器 ​

delay ​

Getter 簽章 ​

get delay(): Delay<Context, EventPayloadMapping, States, EventOutputMapping> | undefined

定義於: interface.ts:1042

回傳 ​

Delay<Context, EventPayloadMapping, States, EventOutputMapping> | undefined

實作了 ​

State.delay

eventGuards ​

Getter 簽章 ​

get eventGuards(): Partial<EventGuards<EventPayloadMapping, States, Context, Guard<Context>>>

定義於: interface.ts:1021

回傳 ​

Partial<EventGuards<EventPayloadMapping, States, Context, Guard<Context>>>

實作了 ​

State.eventGuards

eventPreconditions ​

Getter 簽章 ​

get eventPreconditions(): Partial<EventPreconditions<EventPayloadMapping, Context, Guard<Context>>>

定義於: interface.ts:1027

Pre-action vetoes: named guards that must all pass before this state handles an event. Optional so existing State implementations remain valid; TemplateState always provides it.

回傳 ​

Partial<EventPreconditions<EventPayloadMapping, Context, Guard<Context>>>

Pre-action vetoes: named guards that must all pass before this state handles an event. Optional so existing State implementations remain valid; TemplateState always provides it.

實作了 ​

State.eventPreconditions

eventReactions ​

Getter 簽章 ​

get eventReactions(): EventReactions<EventPayloadMapping, Context, States, EventOutputMapping>

定義於: interface.ts:1033

回傳 ​

EventReactions<EventPayloadMapping, Context, States, EventOutputMapping>

實作了 ​

State.eventReactions

guards ​

Getter 簽章 ​

get guards(): Guard<Context>

定義於: interface.ts:1017

回傳 ​

Guard<Context>

實作了 ​

State.guards

handlingEvents ​

Getter 簽章 ​

get handlingEvents(): keyof EventPayloadMapping[]

定義於: interface.ts:1011

回傳 ​

keyof EventPayloadMapping[]

方法 ​

beforeExit() ​

beforeExit(context, stateMachine, to): void

定義於: interface.ts:1061

參數 ​

context ​

Context

stateMachine ​

StateMachine<EventPayloadMapping, Context, States, EventOutputMapping>

to ​

"TERMINAL" | States

回傳 ​

void

實作了 ​

State.beforeExit

handles() ​

handles<K>(args, context, stateMachine): EventResult<States, K extends keyof EventOutputMapping ? EventOutputMapping[K<K>] : void>

定義於: interface.ts:1074

型別參數 ​

K ​

K extends string | number | symbol

參數 ​

args ​

EventArgs<EventPayloadMapping, K>

context ​

Context

stateMachine ​

StateMachine<EventPayloadMapping, Context, States, EventOutputMapping>

回傳 ​

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

實作了 ​

State.handles

uponEnter() ​

uponEnter(context, stateMachine, from): void

定義於: interface.ts:1048

參數 ​

context ​

Context

stateMachine ​

StateMachine<EventPayloadMapping, Context, States, EventOutputMapping>

from ​

"INITIAL" | States

回傳 ​

void

實作了 ​

State.uponEnter