fix(smartstate): prevent duplicate statepart creation and fix persistence/notification race conditions

ts/smartstate.classes.smartstate.ts

@@ -9,6 +9,8 @@ export type TInitMode = 'soft' | 'mandatory' | 'force' | 'persistent';
 export class Smartstate<StatePartNameType extends string> {
   public statePartMap: { [key in StatePartNameType]?: StatePart<StatePartNameType, any> } = {};
 
+  private pendingStatePartCreation: Map<string, Promise<StatePart<StatePartNameType, any>>> = new Map();
+
   constructor() {}
 
   /**
@@ -26,8 +28,14 @@ export class Smartstate<StatePartNameType extends string> {
     initialArg?: PayloadType,
     initMode: TInitMode = 'soft'
   ): Promise<StatePart<StatePartNameType, PayloadType>> {
+    // Return pending creation if one exists to prevent duplicate state parts
+    const pending = this.pendingStatePartCreation.get(statePartNameArg);
+    if (pending) {
+      return pending as Promise<StatePart<StatePartNameType, PayloadType>>;
+    }
+
     const existingStatePart = this.statePartMap[statePartNameArg];
-    
+
     if (existingStatePart) {
       switch (initMode) {
         case 'mandatory':
@@ -36,7 +44,7 @@ export class Smartstate<StatePartNameType extends string> {
           );
         case 'force':
           // Force mode: create new state part
-          return this.createStatePart<PayloadType>(statePartNameArg, initialArg, initMode);
+          break; // Fall through to creation
         case 'soft':
         case 'persistent':
         default:
@@ -50,7 +58,16 @@ export class Smartstate<StatePartNameType extends string> {
           `State part '${statePartNameArg}' does not exist and no initial state provided`
         );
       }
-      return this.createStatePart<PayloadType>(statePartNameArg, initialArg, initMode);
+    }
+
+    const creationPromise = this.createStatePart<PayloadType>(statePartNameArg, initialArg, initMode);
+    this.pendingStatePartCreation.set(statePartNameArg, creationPromise);
+
+    try {
+      const result = await creationPromise;
+      return result;
+    } finally {
+      this.pendingStatePartCreation.delete(statePartNameArg);
     }
   }
 
@@ -76,10 +93,18 @@ export class Smartstate<StatePartNameType extends string> {
     );
     await newState.init();
     const currentState = newState.getState();
-    await newState.setState({
-      ...currentState,
-      ...initialPayloadArg,
-    });
+
+    if (initMode === 'persistent' && currentState !== undefined) {
+      // Persisted state exists - merge with defaults, persisted values take precedence
+      await newState.setState({
+        ...initialPayloadArg,
+        ...currentState,
+      });
+    } else {
+      // No persisted state or non-persistent mode
+      await newState.setState(initialPayloadArg);
+    }
+
     this.statePartMap[statePartName] = newState;
     return newState;
   }