Root out SCXML-related wrappers (#3971)

* Root out SCXML-related wrappers * remove more things * fix things * fixed escalate * remove redundant casts to any * add changeset
statelyai · May 11, 2023 · d0ba42c · d0ba42c
1 parent 633ca76
commit d0ba42c
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Showing 45 changed files with 308 additions and 946 deletions.
diff --git a/.changeset/rotten-wombats-pump.md b/.changeset/rotten-wombats-pump.md
@@ -0,0 +1,5 @@
+---
+'xstate': major
+---
+
+`_event` has been removed from all APIs and types. It was a wrapper structure containing the `event` that users were using directly.
diff --git a/packages/core/src/State.ts b/packages/core/src/State.ts
@@ -18,18 +18,11 @@ import type {
   MachineContext,
   PersistedMachineState,
   Prop,
-  SCXML,
   StateConfig,
   StateValue,
   TransitionDefinition
 } from './types.ts';
-import {
-  flatten,
-  isString,
-  matchesState,
-  toSCXMLEvent,
-  warn
-} from './utils.ts';
+import { flatten, isString, matchesState, warn } from './utils.ts';
 
 export function isStateConfig<
   TContext extends MachineContext,
@@ -39,7 +32,7 @@ export function isStateConfig<
     return false;
   }
 
-  return 'value' in state && '_event' in state;
+  return 'value' in state && 'event' in state;
 }
 
 /**
@@ -66,8 +59,7 @@ export class State<
   public historyValue: Readonly<HistoryValue<TContext, TEvent>> = {};
   public actions: BaseActionObject[] = [];
   public event: TEvent;
-  public _internalQueue: Array<SCXML.Event<TEvent>>;
-  public _event: SCXML.Event<TEvent>;
+  public _internalQueue: Array<TEvent>;
   public _initial: boolean = false;
   /**
    * Indicates whether the state has changed from the previous state. A state is considered "changed" if:
@@ -109,7 +101,7 @@ export class State<
           {
             value: stateValue.value,
             context,
-            _event: stateValue._event,
+            event: stateValue.event,
             actions: [],
             meta: {},
             configuration: [], // TODO: fix,
@@ -123,7 +115,7 @@ export class State<
       return stateValue;
     }
 
-    const _event = createInitEvent({}) as unknown as SCXML.Event<TEvent>; // TODO: fix
+    const event = createInitEvent({}) as unknown as TEvent; // TODO: fix
 
     const configuration = getConfiguration(
       getStateNodes(machine.root, stateValue)
@@ -133,7 +125,7 @@ export class State<
       {
         value: stateValue,
         context,
-        _event,
+        event,
         actions: [],
         meta: undefined,
         configuration: Array.from(configuration),
@@ -154,9 +146,8 @@ export class State<
     public machine: AnyStateMachine
   ) {
     this.context = config.context;
-    this._event = config._event;
     this._internalQueue = config._internalQueue ?? [];
-    this.event = this._event.data;
+    this.event = config.event;
     this.historyValue = config.historyValue || {};
     this.actions = config.actions ?? [];
     this.matches = this.matches.bind(this);
@@ -242,10 +233,7 @@ export class State<
       );
     }
 
-    const transitionData = this.machine.getTransitionData(
-      this,
-      toSCXMLEvent(event)
-    );
+    const transitionData = this.machine.getTransitionData(this, event);
 
     return (
       !!transitionData?.length &&

diff --git a/packages/core/src/StateMachine.ts b/packages/core/src/StateMachine.ts
@@ -35,20 +35,16 @@ import type {
   MachineImplementationsSimplified,
   MachineTypes,
   NoInfer,
-  SCXML,
   StateConfig,
   StateMachineDefinition,
   StateValue,
   TransitionDefinition,
   PersistedMachineState,
   ParameterizedObject,
-  AnyActorContext
+  AnyActorContext,
+  AnyEventObject
 } from './types.ts';
-import {
-  isSCXMLErrorEvent,
-  resolveReferencedActor,
-  toSCXMLEvent
-} from './utils.ts';
+import { isErrorEvent, resolveReferencedActor } from './utils.ts';
 
 export const NULL_EVENT = '';
 export const STATE_IDENTIFIER = '#';
@@ -77,7 +73,7 @@ export class StateMachine<
   >
 > implements
     ActorBehavior<
-      TEvent | SCXML.Event<TEvent>,
+      TEvent,
       State<TContext, TEvent, TResolvedTypesMeta>,
       State<TContext, TEvent, TResolvedTypesMeta>,
       PersistedMachineState<State<TContext, TEvent, TResolvedTypesMeta>>
@@ -237,23 +233,20 @@ export class StateMachine<
   public transition(
     state: State<TContext, TEvent, TResolvedTypesMeta> | StateValue = this
       .initialState,
-    event: TEvent | SCXML.Event<TEvent>,
+    event: TEvent,
     actorCtx?: ActorContext<TEvent, State<TContext, TEvent, any>>
   ): State<TContext, TEvent, TResolvedTypesMeta> {
     const currentState =
       state instanceof State ? state : this.resolveStateValue(state);
     // TODO: handle error events in a better way
-    const scxmlEvent = toSCXMLEvent(event);
     if (
-      isSCXMLErrorEvent(scxmlEvent) &&
-      !currentState.nextEvents.some(
-        (nextEvent) => nextEvent === scxmlEvent.name
-      )
+      isErrorEvent(event) &&
+      !currentState.nextEvents.some((nextEvent) => nextEvent === event.type)
     ) {
-      throw scxmlEvent.data.data;
+      throw event.data;
     }
 
-    const { state: nextState } = macrostep(currentState, scxmlEvent, actorCtx);
+    const { state: nextState } = macrostep(currentState, event, actorCtx);
 
     return nextState;
   }
@@ -267,21 +260,17 @@ export class StateMachine<
    */
   public microstep(
     state: State<TContext, TEvent, TResolvedTypesMeta> = this.initialState,
-    event: TEvent | SCXML.Event<TEvent>,
+    event: TEvent,
     actorCtx?: AnyActorContext | undefined
   ): Array<State<TContext, TEvent, TResolvedTypesMeta>> {
-    const scxmlEvent = toSCXMLEvent(event);
-
-    const { microstates } = macrostep(state, scxmlEvent, actorCtx);
-
-    return microstates;
+    return macrostep(state, event, actorCtx).microstates;
   }
 
   public getTransitionData(
     state: State<TContext, TEvent, TResolvedTypesMeta>,
-    _event: SCXML.Event<TEvent>
+    event: TEvent
   ): Array<TransitionDefinition<TContext, TEvent>> {
-    return transitionNode(this.root, state.value, state, _event) || [];
+    return transitionNode(this.root, state.value, state, event) || [];
   }
 
   /**
@@ -298,7 +287,7 @@ export class StateMachine<
       this.createState({
         value: {}, // TODO: this is computed in state constructor
         context,
-        _event: createInitEvent({}) as unknown as SCXML.Event<TEvent>,
+        event: createInitEvent({}) as unknown as TEvent,
         actions: [],
         meta: undefined,
         configuration: config,
@@ -312,7 +301,7 @@ export class StateMachine<
     if (actorCtx) {
       const { nextState } = resolveActionsAndContext(
         actions,
-        initEvent as SCXML.Event<TEvent>,
+        initEvent as TEvent,
         preInitial,
         actorCtx
       );
@@ -341,13 +330,17 @@ export class StateMachine<
     >,
     input?: any
   ): State<TContext, TEvent, TResolvedTypesMeta> {
-    const initEvent = createInitEvent(input) as unknown as SCXML.Event<TEvent>; // TODO: fix;
+    const initEvent = createInitEvent(input) as unknown as TEvent; // TODO: fix;
 
     const preInitialState = this.getPreInitialState(actorCtx, input);
     const nextState = microstep([], preInitialState, actorCtx, initEvent);
     nextState.actions.unshift(...preInitialState.actions);
 
-    const { state: macroState } = macrostep(nextState, initEvent, actorCtx);
+    const { state: macroState } = macrostep(
+      nextState,
+      initEvent as AnyEventObject,
+      actorCtx
+    );
 
     return macroState;
   }
@@ -414,7 +407,7 @@ export class StateMachine<
 
     const { nextState: resolvedState } = resolveActionsAndContext(
       state.actions,
-      state._event,
+      state.event,
       state,
       undefined
     );

diff --git a/packages/core/src/StateNode.ts b/packages/core/src/StateNode.ts
@@ -20,7 +20,6 @@ import type {
   InvokeDefinition,
   Mapper,
   PropertyMapper,
-  SCXML,
   TransitionDefinitionMap,
   InitialTransitionDefinition,
   MachineContext,
@@ -115,7 +114,7 @@ export class StateNode<
     | Mapper<TContext, TEvent, any>
     | PropertyMapper<TContext, TEvent, any>;
   /**
-   * The order this state node appears. Corresponds to the implicit SCXML document order.
+   * The order this state node appears. Corresponds to the implicit document order.
    */
   public order: number = -1;
 
@@ -335,20 +334,20 @@ export class StateNode<
 
   public next(
     state: State<TContext, TEvent>,
-    _event: SCXML.Event<TEvent>
+    event: TEvent
   ): TransitionDefinition<TContext, TEvent>[] | undefined {
-    const eventName = _event.name;
+    const eventType = event.type;
     const actions: BaseActionObject[] = [];
 
     let selectedTransition: TransitionDefinition<TContext, TEvent> | undefined;
 
     const candidates: Array<TransitionDefinition<TContext, TEvent>> = memo(
       this,
-      `candidates-${eventName.toString()}`,
+      `candidates-${eventType.toString()}`,
       () =>
         getCandidates(
           this,
-          eventName,
+          eventType,
           this.machine.config.scxml // Whether token matching should be used
         )
     );
@@ -362,17 +361,12 @@ export class StateNode<
       try {
         guardPassed =
           !guard ||
-          evaluateGuard<TContext, TEvent>(
-            guard,
-            resolvedContext,
-            _event,
-            state
-          );
+          evaluateGuard<TContext, TEvent>(guard, resolvedContext, event, state);
       } catch (err) {
         throw new Error(
           `Unable to evaluate guard '${
             guard!.type
-          }' in transition for event '${eventName}' in state node '${
+          }' in transition for event '${eventType}' in state node '${
             this.id
           }':\n${err.message}`
         );

diff --git a/packages/core/src/actions.ts b/packages/core/src/actions.ts
@@ -9,11 +9,10 @@ import {
   ErrorPlatformEvent,
   DoneEventObject,
   MachineContext,
-  BaseActionObject,
-  SCXML
+  BaseActionObject
 } from './types.ts';
 import * as actionTypes from './actionTypes.ts';
-import { toSCXMLEvent, isArray } from './utils.ts';
+import { isArray } from './utils.ts';
 import {
   createDynamicAction,
   isDynamicAction
@@ -22,7 +21,6 @@ export {
   send,
   sendTo,
   sendParent,
-  respond,
   forwardTo,
   escalate
 } from './actions/send.ts';
@@ -36,7 +34,7 @@ export { choose } from './actions/choose.ts';
 export { pure } from './actions/pure.ts';
 export { actionTypes };
 
-export const initEvent = toSCXMLEvent({ type: actionTypes.init });
+export const initEvent = { type: actionTypes.init };
 
 export function resolveActionObject(
   actionObject: BaseActionObject,
@@ -50,16 +48,15 @@ export function resolveActionObject(
   if (typeof dereferencedAction === 'function') {
     return createDynamicAction(
       { type: 'xstate.function', params: actionObject.params ?? {} },
-      (_event, { state }) => {
+      (event, { state }) => {
         const a: BaseActionObject = {
           type: actionObject.type,
           params: actionObject.params,
           execute: (actorCtx) => {
             return dereferencedAction({
               context: state.context,
-              event: _event.data,
+              event,
               action: a,
-              _event: _event,
               system: actorCtx.system,
               self: actorCtx.self
             });
@@ -92,7 +89,7 @@ export function toActionObject<
 
   if (typeof action === 'function') {
     const type = 'xstate.function';
-    return createDynamicAction({ type, params: {} }, (_event, { state }) => {
+    return createDynamicAction({ type, params: {} }, (event, { state }) => {
       const actionObject: BaseActionObject = {
         type,
         params: {
@@ -101,9 +98,8 @@ export function toActionObject<
         execute: (actorCtx) => {
           return action({
             context: state.context as TContext,
-            event: _event.data as TEvent,
+            event: event as TEvent,
             action: actionObject,
-            _event: _event as SCXML.Event<TEvent>,
             self: actorCtx.self,
             system: actorCtx.system
           });
@@ -192,8 +188,6 @@ export function error(id: string, data?: any): ErrorPlatformEvent & string {
   return eventObject as ErrorPlatformEvent & string;
 }
 
-export function createInitEvent(
-  input: any
-): SCXML.Event<{ type: ActionTypes.Init; input: any }> {
-  return toSCXMLEvent({ type: actionTypes.init, input });
+export function createInitEvent(input: any) {
+  return { type: actionTypes.init, input } as const;
 }
diff --git a/packages/core/src/actions/assign.ts b/packages/core/src/actions/assign.ts
@@ -44,7 +44,7 @@ export function assign<
         assignment
       }
     },
-    (_event, { state, action, actorContext }) => {
+    (event, { state, action, actorContext }) => {
       const capturedActions: InvokeActionObject[] = [];
 
       if (!state.context) {
@@ -58,14 +58,13 @@ export function assign<
         event: TExpressionEvent;
       } = {
         context: state.context,
-        event: _event.data,
+        event,
         action,
-        _event,
         spawn: createSpawner(
           actorContext?.self,
           state.machine,
           state.context,
-          _event,
+          event,
           capturedActions
         ),
         self: actorContext?.self ?? ({} as any),