Bugfix/rx stateful no subs values (#112)

* #111 fix(rx-stateful): fix not emitting subsequent values

The issue was caused when a source does not emit a thruthy value. This is e.g. the case for Endpoints which send an empty response back, e.g. after a delete-operation.

The problem can easiliy be simulated by
```ts
rxStateful$(
 timer(1000).pipe(switchMap(() => of(null)))
)
```

* chore: ehnance demos

apps/demo-rx-stateful/src/app/all-use-cases/all-use-cases.component.html

@@ -0,0 +1,41 @@
+<!--<div>-->
+<!--  <h1>Case 1</h1>-->
+<!--  <div>-->
+<!--    <button (click)="refresh$$.next(null)">refresh</button>-->
+<!--    <div>-->
+<!--      @if(case1$ | async ; as data){-->
+<!--        <rx-stateful-state-visualizer [state]="data"/>-->
+<!--      }-->
+<!--    </div>-->
+<!--  </div>-->
+<!--</div>-->
+
+
+<div>
+  <h1>Bugfix Reproduction</h1>
+  <div>
+    <button (click)="deleteAction$.next(1)">trigger delete</button>
+    <div>
+      @if(delete$ | async ; as data){
+        <rx-stateful-state-visualizer [state]="data"/>
+      }
+    </div>
+  </div>
+</div>
+
+
+
+
+<div>
+  <h1>Bugfix Reproduction Normal Case</h1>
+  <div>
+    <button (click)="refresh$.next(null)">trigger refresh</button>
+    <div>
+      @if(two$ | async ; as data){
+        <rx-stateful-state-visualizer [state]="data"/>
+      }
+    </div>
+  </div>
+</div>
+
+<demo-non-flicker/>

apps/demo-rx-stateful/src/app/all-use-cases/all-use-cases.component.scss

@@ -0,0 +1,6 @@
+button{
+  padding: 8px 16px;
+  border-radius: 9999px;
+  font-weight: bold;
+  border: 2px solid deepskyblue;
+}

apps/demo-rx-stateful/src/app/all-use-cases/all-use-cases.component.spec.ts

@@ -0,0 +1,21 @@
+import { ComponentFixture, TestBed } from '@angular/core/testing';
+import { AllUseCasesComponent } from './all-use-cases.component';
+
+describe('AllUseCasesComponent', () => {
+  let component: AllUseCasesComponent;
+  let fixture: ComponentFixture<AllUseCasesComponent>;
+
+  beforeEach(async () => {
+    await TestBed.configureTestingModule({
+      imports: [AllUseCasesComponent],
+    }).compileComponents();
+
+    fixture = TestBed.createComponent(AllUseCasesComponent);
+    component = fixture.componentInstance;
+    fixture.detectChanges();
+  });
+
+  it('should create', () => {
+    expect(component).toBeTruthy();
+  });
+});

apps/demo-rx-stateful/src/app/all-use-cases/all-use-cases.component.ts

@@ -0,0 +1,151 @@
+import {Component, inject, Injectable} from '@angular/core';
+import { CommonModule } from '@angular/common';
+import {HttpClient, HttpErrorResponse} from "@angular/common/http";
+import {delay, Observable, of, OperatorFunction, scan, Subject, switchMap, timer} from "rxjs";
+import {RxStateful, rxStateful$, withAutoRefetch, withRefetchOnTrigger} from "@angular-kit/rx-stateful";
+import {Todo} from "../types";
+import {RxStatefulStateVisualizerComponent} from "./rx-stateful-state-visualizer.component";
+import {NonFlickerComponent} from "./non-flicker/non-flicker.component";
+
+type Data = {
+  id: number;
+  name: string
+}
+
+const DATA: Data[] = [
+  {id: 1, name: 'ahsd'},
+  {id: 2, name: 'asdffdsa'},
+  {id: 3, name: 'eeasdf'},
+]
+
+@Injectable({providedIn: 'root'})
+export class DataService {
+  private readonly http = inject(HttpClient)
+
+
+  getData(opts?: {delay?: number}){
+    return timer(opts?.delay ?? 1000).pipe(
+      switchMap(() => of(DATA))
+    )
+  }
+
+  getById(id: number, opts?: {delay?: number}){
+    return timer(opts?.delay ?? 1000).pipe(
+      switchMap(() => of(DATA.find(v =>v.id === id)))
+    )
+  }
+}
+
+@Component({
+  selector: 'demo-all-use-cases',
+  standalone: true,
+  imports: [CommonModule, RxStatefulStateVisualizerComponent, NonFlickerComponent],
+  templateUrl: './all-use-cases.component.html',
+  styleUrl: './all-use-cases.component.scss',
+})
+export class AllUseCasesComponent {
+  private readonly http = inject(HttpClient)
+  private readonly data = inject(DataService)
+  readonly refresh$$ = new Subject<null>()
+  refreshInterval = 10000
+  /**
+   * Für alle Use Cases eine demo machen
+   */
+
+  /**
+   * Case 1
+   * Basic Usage with automatic refetch and a refreshtrigger
+   */
+  case1$ = rxStateful$<Data[], Error>(
+    this.data.getData(),
+    {
+      refetchStrategies: [
+        withRefetchOnTrigger(this.refresh$$),
+        //withAutoRefetch(this.refreshInterval, 1000000)
+      ],
+      suspenseThresholdMs: 0,
+      suspenseTimeMs: 0,
+      keepValueOnRefresh: false,
+      keepErrorOnRefresh: false,
+      errorMappingFn: (error) => error.message,
+    }
+  ).pipe(
+    collectState()
+  )
+
+  /**
+   * Case Basic Usage non flickering
+   */
+
+  /**
+   * Case Basic Usage flaky API
+   */
+  //case2$
+
+  /**
+   * Case - sourcetrigger function
+   */
+
+
+  /**
+   * Case  - sourcetrigger function non flickering
+   */
+
+  /**
+   * Case - sourcetrigger function flaky api
+   */
+
+  /**
+   * Case Bug Reproduction  https://github.com/mikelgo/angular-kit/issues/111
+   */
+
+  deleteAction$ = new Subject<number>()
+
+  delete$ = rxStateful$(
+    // id => this.http.get(`https://jsonplaceholder.typicode.com/posts/${id}`),
+    id => timer(1000).pipe(
+      switchMap(() => of(null))
+    ),
+    {
+      suspenseTimeMs: 0,
+      suspenseThresholdMs: 0,
+      sourceTriggerConfig: {
+        operator: 'switch',
+        trigger: this.deleteAction$
+      }
+    }
+  ).pipe(
+    collectState()
+  )
+
+  /**
+   * Case Normal for Bug repro
+   */
+  refresh$ = new Subject<null>()
+  two$ = rxStateful$(
+    timer(1000).pipe(
+      switchMap(() => of(null))
+    ),
+    {
+      refetchStrategies: [withRefetchOnTrigger(this.refresh$)]
+    }
+  ).pipe(
+    collectState()
+  )
+}
+
+
+function collectState(): OperatorFunction<RxStateful<any>, {
+  index: number;
+  value: RxStateful<any>
+}[]>{
+  return    scan<RxStateful<any>, {
+    index: number;
+    value: RxStateful<any>
+  }[]>((acc, value, index) => {
+    // @ts-ignore
+    acc.push({ index, value });
+
+    return acc;
+  }, [])
+}

apps/demo-rx-stateful/src/app/all-use-cases/non-flicker/non-flicker.component.ts

@@ -0,0 +1,167 @@
+import {Component, inject} from '@angular/core';
+import { CommonModule } from '@angular/common';
+import {HttpClient} from "@angular/common/http";
+import {ActivatedRoute} from "@angular/router";
+import {BehaviorSubject, concatAll, delay, map, scan, Subject, switchMap, tap, toArray} from "rxjs";
+import {provideRxStatefulClient, RxStatefulClient, withConfig} from "@angular-kit/rx-stateful/experimental";
+import {rxStateful$, withRefetchOnTrigger} from "@angular-kit/rx-stateful";
+
+@Component({
+  selector: 'demo-non-flicker',
+  standalone: true,
+  imports: [CommonModule],
+  template: `
+    <h1>DemoRxStatefulComponent</h1>
+<!--    <div>-->
+<!--      <button (click)="refresh$$.next(null)">refresh</button>-->
+<!--    </div>-->
+<!--    <div>-->
+<!--      <h4>State</h4>-->
+<!--      <div *ngIf="state$ | async as state">-->
+<!--        <div *ngIf="state.value">{{ state.value | json }}</div>-->
+<!--        <div *ngIf="state.isSuspense">loading</div>-->
+<!--      </div>-->
+<!--    </div>-->
+<!--    <div>-->
+<!--      <h4>State Accumulated</h4>-->
+<!--      <ul *ngFor="let v of stateAccumulated$ | async">-->
+<!--        <li>{{ v | json }}</li>-->
+<!--      </ul>-->
+<!--    </div>-->
+    <!--    <div>-->
+    <!--      <h4>Query Params</h4>-->
+    <!--      <div>{{ query$ | async | json }}</div>-->
+    <!--      <div>{{ value$ | async | json }}</div>-->
+    <!--    </div>-->
+
+    <!--    <br>-->
+        <div>
+          <button mat-button color="primary" (click)="page$$.next(-1)"> previous page </button>
+          <button mat-button color="primary" (click)="page$$.next(1)"> next page </button>
+          <button mat-button color="primary" (click)="refresh$$.next(null)"> Refresh current page </button>
+          <div>
+            <h4>State Accumulated</h4>
+            <ul *ngFor="let v of state2Accumulated$ | async">
+              <li>{{ v | json }}</li>
+            </ul>
+          </div>
+        </div>
+  `,
+  styles: `
+    :host {
+      display: block;
+    }
+  `,
+  providers: [
+    provideRxStatefulClient(
+      withConfig({ keepValueOnRefresh: false, errorMappingFn: (e) => e})
+    ),
+    // provideRxStatefulConfig({keepValueOnRefresh: true, errorMappingFn: (e) => e})
+  ],
+})
+export class NonFlickerComponent {
+  private http = inject(HttpClient);
+  private route = inject(ActivatedRoute);
+  refresh$$ = new Subject<any>();
+
+  client = inject(RxStatefulClient);
+
+  query$ = this.route.params;
+
+  value$ = this.query$.pipe(switchMap(() => this.client.request(this.fetch()).pipe(
+    map(v => v.value)
+  )));
+
+  // instance = this.client.request(this.fetch(), {
+  //   keepValueOnRefresh: false,
+  //   keepErrorOnRefresh: false,
+  //   refreshTrigger$: this.refresh$$,
+  //   refetchStrategies: [withAutoRefetch(10000, 20000)],
+  // });
+  // state$ = this.instance;
+  // stateAccumulated$ = this.state$.pipe(
+  //   tap(console.log),
+  //   scan((acc, value, index) => {
+  //     @ts-ignore
+  // acc.push({ index, value });
+  //
+  // return acc;
+  // }, [])
+  // );
+
+
+  state$ = rxStateful$(this.fetch(450), {
+    keepValueOnRefresh: false,
+    keepErrorOnRefresh: false,
+    refreshTrigger$: this.refresh$$,
+    suspenseTimeMs: 3000,
+    suspenseThresholdMs: 500
+  });
+
+  stateAccumulated$ = this.state$.pipe(
+    tap(x => console.log({state: x})),
+    scan((acc, value, index) => {
+      // @ts-ignore
+      acc.push({ index, value });
+
+      return acc;
+    }, [])
+  );
+  readonly page$$ = new BehaviorSubject(0)
+  readonly page$ = this.page$$.pipe(
+    scan((acc, curr) => acc + curr, 0)
+  )
+
+  state2$ = rxStateful$(
+    (page) => this.fetchPage({
+      page,
+      delayInMs: 5000
+    }).pipe(
+
+    ),
+    {
+      suspenseThresholdMs: 500,
+      suspenseTimeMs: 2000,
+      sourceTriggerConfig: {
+        trigger: this.page$
+      },
+      refetchStrategies: withRefetchOnTrigger(this.refresh$$)
+    }
+  )
+  state2Accumulated$ = this.state2$.pipe(
+    tap(x => console.log({state: x})),
+    scan((acc, value, index) => {
+      // @ts-ignore
+      acc.push({ index, value });
+
+      return acc;
+    }, [])
+  );
+
+  fetch(delayInMs = 800) {
+    return this.http.get<any>('https://jsonplaceholder.typicode.com/todos/1').pipe(
+      delay(delayInMs),
+      map((v) => v?.title),
+      // tap(console.log)
+    );
+  }
+
+  fetchPage(params: {
+    delayInMs:number,
+    page: number
+  }) {
+
+    return this.http.get<any>(`https://jsonplaceholder.typicode.com/todos?_start=${params.page * 5}&_limit=5`).pipe(
+      delay(params.delayInMs),
+      concatAll(),
+      // @ts-ignore
+      map((v) => v?.id),
+      toArray()
+    );
+  }
+
+  constructor() {
+    this.state$.subscribe();
+    this.state$.subscribe();
+  }
+}