Merge pull request #129 from AceFire6/jethro/change/initial-state-fun…

…c-async feat(actor): allow async initialStateFunc
nactio · Dec 12, 2022 · 045360a · 045360a
2 parents ef0629a + 5f9f9a1
commit 045360a
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Showing 2 changed files with 63 additions and 7 deletions.
diff --git a/@nact/core/actor.test.ts b/@nact/core/actor.test.ts
@@ -164,6 +164,56 @@ describe('Actor', function () {
       handled.should.be.true;
     });
 
+    it('correctly handles an asynchronous initial state function', async function () {
+      let actor = spawn(
+        system,
+        function (state, msg) {
+          if (msg.type === 'query') {
+            dispatch(msg.sender, state);
+            return state;
+          } else if (msg.type === 'append') {
+            return state + msg.payload;
+          }
+        },
+        {
+          name: 'Nact',
+          initialStateFunc: async () => {
+            await new Promise(f => setTimeout(f, 20));
+            return 'Cheese!';
+            },
+        }
+      );
+
+      dispatch(actor, { payload: ' Magical wheels of golden hue!', type: 'append' });
+      let result = await query(actor, x => ({ type: 'query', sender: x }), 30);
+      result.should.equal('Cheese! Magical wheels of golden hue!');
+    });
+
+    it('correctly handles an async initial state function which throws an error', async function () {
+      let handled = false;
+      let actor = spawn(
+        system,
+        function (state, msg) {
+          if (msg.type === 'query') {
+            dispatch(msg.sender, state);
+            return state;
+          } else if (msg.type === 'append') {
+            return state + msg.payload;
+          }
+        },
+        {
+          name: 'Nact',
+          initialStateFunc: async () => {
+            await new Promise(f => setTimeout(f, 15));
+            throw new Error('A bad moon is on the rise');
+          },
+          onCrash: (_: any, __: any, ctx: { stop: any; }) => { handled = true; return ctx.stop; }
+        }
+      );
+      await retry(() => isStopped(actor).should.be.true, 12, 10);
+      handled.should.be.true;
+    });
+
     it('evalutes in order when returning a promise from a stateful actor function', async function () {
       let child = spawn(
         system,

diff --git a/@nact/core/actor.ts b/@nact/core/actor.ts
@@ -56,7 +56,8 @@ export class Actor<State, Msg, ParentRef extends LocalActorSystemRef | LocalActo
   immediate: number | undefined;
   onCrash: SupervisionActorFunc<Msg, ParentRef> | ((msg: any, err: any, ctx: any, child?: undefined | LocalActorRef<unknown>) => any);
   initialState: State | undefined;
-  initialStateFunc: ((ctx: ActorContext<Msg, ParentRef>) => State) | undefined;
+  initialStateFunc: ((ctx: ActorContext<Msg, ParentRef>) => State | Promise<State>) | undefined;
+  initializeStatePromise: Promise<void>
   shutdownPeriod?: Milliseconds;
   state: any;
   timeout?: Milliseconds;
@@ -101,16 +102,20 @@ export class Actor<State, Msg, ParentRef extends LocalActorSystemRef | LocalActo
     } else {
       this.setTimeout = unit;
     }
-    this.initializeState();
+    this.initializeStatePromise = this.initializeState();
     this.setTimeout();
   }
 
-  initializeState() {
+  async waitUntilInitialized() {
+    await this.initializeStatePromise;
+  }
+
+  async initializeState() {
     if (this.initialStateFunc) {
       try {
-        this.state = this.initialStateFunc(this.createContext());
+        this.state = await Promise.resolve(this.initialStateFunc(this.createContext()));
       } catch (e) {
-        this.handleFault(undefined, e as Error | undefined);
+        await this.handleFault(undefined, e as Error | undefined);
       }
     } else {
       this.state = this.initialState;
@@ -120,7 +125,7 @@ export class Actor<State, Msg, ParentRef extends LocalActorSystemRef | LocalActo
 
   reset() {
     [...this.children.values()].forEach(x => x.stop());
-    this.initializeState();
+    this.initializeStatePromise = this.initializeState();
     this.resume();
   }
 
@@ -287,6 +292,7 @@ export class Actor<State, Msg, ParentRef extends LocalActorSystemRef | LocalActo
     this.busy = true;
     this.immediate = addMacrotask(async () => {
       try {
+        await this.waitUntilInitialized();
         let ctx = this.createContext();
         let next = await Promise.resolve(this.f.call(ctx, this.state, message, ctx));
         this.state = next;
@@ -350,7 +356,7 @@ export type ActorProps<State, Msg, ParentRef extends ActorSystemRef | LocalActor
   shutdownAfter?: Milliseconds,
   onCrash?: SupervisionActorFunc<Msg, ParentRef>,
   initialState?: State,
-  initialStateFunc?: (ctx: ActorContext<Msg, ParentRef>) => State,
+  initialStateFunc?: (ctx: ActorContext<Msg, ParentRef>) => State | Promise<State>,
   afterStop?: (state: State, ctx: ActorContext<Msg, ParentRef>) => void | Promise<void>
 };