103236: fix issue where setStaleByHrefSubtring wouldn't emit after all requests were stale

src/app/core/data/request.service.ts

@@ -2,8 +2,8 @@ import { Injectable } from '@angular/core';
 import { HttpHeaders } from '@angular/common/http';
 
 import { createSelector, MemoizedSelector, select, Store } from '@ngrx/store';
-import { Observable } from 'rxjs';
-import { filter, map, take, tap } from 'rxjs/operators';
+import { Observable, from as observableFrom } from 'rxjs';
+import { filter, find, map, mergeMap, switchMap, take, tap, toArray } from 'rxjs/operators';
 import { cloneDeep } from 'lodash';
 import { hasValue, isEmpty, isNotEmpty, hasNoValue } from '../../shared/empty.util';
 import { ObjectCacheEntry } from '../cache/object-cache.reducer';
@@ -292,22 +292,42 @@ export class RequestService {
    * Set all requests that match (part of) the href to stale
    *
    * @param href    A substring of the request(s) href
-   * @return        Returns an observable emitting whether or not the cache is removed
+   * @return        Returns an observable emitting when those requests are all stale
    */
   setStaleByHrefSubstring(href: string): Observable<boolean> {
-    this.store.pipe(
+    const requestUUIDs$ = this.store.pipe(
       select(uuidsFromHrefSubstringSelector(requestIndexSelector, href)),
       take(1)
-    ).subscribe((uuids: string[]) => {
+    );
+    requestUUIDs$.subscribe((uuids: string[]) => {
       for (const uuid of uuids) {
         this.store.dispatch(new RequestStaleAction(uuid));
       }
     });
     this.requestsOnTheirWayToTheStore = this.requestsOnTheirWayToTheStore.filter((reqHref: string) => reqHref.indexOf(href) < 0);
 
-    return this.store.pipe(
-      select(uuidsFromHrefSubstringSelector(requestIndexSelector, href)),
-      map((uuids) => isEmpty(uuids))
+    // emit true after all requests are stale
+    return requestUUIDs$.pipe(
+      switchMap((uuids: string[]) => {
+        if (isEmpty(uuids)) {
+          // if there were no matching requests, emit true immediately
+          return [true];
+        } else {
+          // otherwise emit all request uuids in order
+          return observableFrom(uuids).pipe(
+            // retrieve the RequestEntry for each uuid
+            mergeMap((uuid: string) => this.getByUUID(uuid)),
+            // check whether it is undefined or stale
+            map((request: RequestEntry) => hasNoValue(request) || isStale(request.state)),
+            // if it is, complete
+            find((stale: boolean) => stale === true),
+            // after all observables above are completed, emit them as a single array
+            toArray(),
+            // when the array comes in, emit true
+            map(() => true)
+          );
+        }
+      })
     );
   }