Interface FsmEventBuilder<State, Events, Context, K>

Builder used to define handling for a particular event within a state or fallback.

Supports begin actions, guarded transitions, and unguarded transitions.

interface FsmEventBuilder<
    State extends string,
    Events extends EventMap,
    Context,
    K extends EventName<Events>,
> {
    begin(action: FsmBeginAction<State, Events, K, Context>): void;
    stay(
        body?: (
            t: FsmTransitionActionsBuilder<State, Events, Context, K>,
        ) => void,
    ): void;
    toState(
        target: State,
        body?: (t: FsmTransitionActionsBuilder<State, Events, Context, K>) => void,
    ): void;
    when(
        cond: FsmGuard<State, Events, K, Context>,
    ): FsmGuardedTransitionBuilder<State, Events, Context, K>;
}

Type Parameters

State extends string
Events extends EventMap
Context
K extends EventName<Events>

Hierarchy

FsmTransitionBuilder<State, Events, Context, K>
- FsmEventBuilder

Index

Methods

begin stay toState when

Methods

begin

begin(action: FsmBeginAction<State, Events, K, Context>): void
Adds a begin action for this event handler.

Begin actions run before any transition for the event is evaluated. Multiple begin actions are allowed and run in declaration order.

See FsmBeginAction for the action function type signature.
Parameters
- action: FsmBeginAction<State, Events, K, Context>
Returns void
- Defined in src/fsm-dsl.ts:158

stay

stay(
    body?: (
        t: FsmTransitionActionsBuilder<State, Events, Context, K>,
    ) => void,
): void
Declares an internal transition.

The machine remains in the current state; state exit and entry actions do not run. The optional body receives a FsmTransitionActionsBuilder for declaring transition actions.
Parameters
- Optionalbody: (t: FsmTransitionActionsBuilder<State, Events, Context, K>) => void
Returns void
Inherited from FsmTransitionBuilder.stay
- Defined in src/fsm-dsl.ts:140

toState

toState(
target: State,
body?: (t: FsmTransitionActionsBuilder<State, Events, Context, K>) => void,
): void
Declares an external transition to target.

The optional body receives a FsmTransitionActionsBuilder for declaring transition actions.

If target is the current state, the machine still performs an external transition: exit actions run, then transition actions, then entry actions.
Parameters
- target: State
- Optionalbody: (t: FsmTransitionActionsBuilder<State, Events, Context, K>) => void
Returns void
Inherited from FsmTransitionBuilder.toState
- Defined in src/fsm-dsl.ts:131

when

when(
cond: FsmGuard<State, Events, K, Context>,
): FsmGuardedTransitionBuilder<State, Events, Context, K>
Starts a guarded transition.

Returns a FsmGuardedTransitionBuilder that allows additional guards to be chained before the final transition is declared.

See FsmGuard for the guard function type signature.
Parameters
- cond: FsmGuard<State, Events, K, Context>
Returns FsmGuardedTransitionBuilder<State, Events, Context, K>
- Defined in src/fsm-dsl.ts:168