Interface KosStateMachineAware<TState, TEvent>

Interface for models using the

Kos State Machine

decorator.

IMPORTANT: Use TypeScript interface merging to add FSM properties to your model class. This provides full type safety and IntelliSense support for all injected FSM functionality.

Interface Merging Pattern

// 1. Define state and event types
type PourState = 'idle' | 'preparing' | 'ready' | 'pouring' | 'error';
type PourEvent = 'PREPARE' | 'READY' | 'POUR' | 'COMPLETE' | 'ERROR';

// 2. Declare interface merging BEFORE the class
interface DispenserModelImpl extends KosStateMachineAware<PourState, PourEvent> {}

// 3. Apply decorators and implement the class
@kosModel({ modelTypeId: "dispenser-model" })
@kosStateMachine<PourState, PourEvent>({
  initial: 'idle',
  initializeAt: DependencyLifecycle.READY,
  states: {
    idle: { on: { PREPARE: 'preparing' } },
    preparing: { on: { READY: 'ready', ERROR: 'error' } },
    ready: { on: { POUR: 'pouring' } },
    pouring: { on: { COMPLETE: 'idle', ERROR: 'error' } },
    error: {}
  }
})
export class DispenserModelImpl implements IKosDataModel {
  // All FSM properties are now available with full type safety
}
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Lifecycle-Aware Initialization

The FSM is uninitialized until the configured lifecycle phase:

• Before initialization: currentState === undefined, isFsmInitialized === false
• After initialization: currentState === initial, isFsmInitialized === true

@kosStateMachine({
  initial: 'idle',
  initializeAt: DependencyLifecycle.READY, // FSM starts when model is ready
  states: { ... }
})
class MyModel {
  async ready(): Promise<void> {
    // Before this completes: this.currentState === undefined
    // After this completes: this.currentState === 'idle'
  }
}
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Injected Properties and Methods

The decorator automatically injects the following members:

• currentState: Current state (undefined until FSM initialized, observable)
• isFsmInitialized: Boolean indicating if FSM has been initialized
• isTransitioning: Boolean indicating if a transition is in progress
• allowedTransitions: Computed array of valid events for current state
• transition(event): Method to trigger state transitions
• canTransition(event): Check if a transition is valid from current state
• isInState(state): Check if currently in a specific state
• stateHistory: Array of historical states (if trackHistory enabled)

All properties are reactive and will automatically update UI components when state changes.

See

• kosStateMachine - The decorator function
• KosStateMachineConfig - Configuration interface
• KosStateMachineOptions - Options interface