ensure getByUUID still returns undefined when there's no match

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

@@ -140,13 +140,21 @@ describe('RequestService', () => {
   describe('getByUUID', () => {
     describe('if the request with the specified UUID exists in the store', () => {
       beforeEach(() => {
-        selectSpy.and.callFake(() => {
-          return () => {
-            return () => hot('a', {
+        let callCounter = 0;
+        const responses = [
+          cold('a', { // A direct hit in the request cache
             a: {
               completed: true
             }
-            });
+          }),
+          cold('b', { b: undefined }), // No hit in the index
+          cold('c', { c: undefined })  // So no mapped hit in the request cache
+        ];
+        selectSpy.and.callFake(() => {
+          return () => {
+            const response = responses[callCounter];
+            callCounter++;
+            return () => response;
           };
         });
       });
@@ -165,17 +173,25 @@ describe('RequestService', () => {
 
     describe(`if the request with the specified UUID doesn't exist in the store `, () => {
       beforeEach(() => {
+        let callCounter = 0;
+        const responses = [
+          cold('a', { a: undefined }), // No direct hit in the request cache
+          cold('b', { b: undefined }), // No hit in the index
+          cold('c', { c: undefined }), // So no mapped hit in the request cache
+        ];
         selectSpy.and.callFake(() => {
           return () => {
-            return () => hot('a', { a: undefined });
+            const response = responses[callCounter];
+            callCounter++;
+            return () => response;
           };
         });
       });
 
-      it(`it shouldn't return anything`, () => {
+      it('should return an Observable of undefined', () => {
         const result = service.getByUUID(testUUID);
 
-        scheduler.expectObservable(result).toBe('');
+        scheduler.expectObservable(result).toBe('a', { a: undefined });
       });
     });
 
@@ -183,13 +199,12 @@ describe('RequestService', () => {
       beforeEach(() => {
         let callCounter = 0;
         const responses = [
-          cold('a', { a: undefined }), // No hit in the request cache with that UUID
+          cold('a', { a: undefined }), // No direct hit in the request cache with that UUID
           cold('b', { b: 'otherRequestUUID' }), // A hit in the index, which returns the uuid of the cached request
-          cold('c', { c: {  // the call to retrieve the cached request using the UUID from the index
+          cold('c', {   // the call to retrieve the cached request using the UUID from the index
             c: {
               completed: true
             }
-            }
           })
         ];
         selectSpy.and.callFake(() => {
@@ -204,11 +219,10 @@ describe('RequestService', () => {
       it(`it should return the cached request`, () => {
         const result = service.getByUUID(testUUID);
 
-        scheduler.expectObservable(result).toBe('c', { c: {
+        scheduler.expectObservable(result).toBe('c', {
           c: {
             completed: true
           }
-          }
         });
       });
     });

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, race as observableRace } from 'rxjs';
-import { filter, map, mergeMap, take, switchMap } from 'rxjs/operators';
+import { Observable, combineLatest as observableCombineLatest } from 'rxjs';
+import { filter, map, mergeMap, take, switchMap, startWith } from 'rxjs/operators';
 import { cloneDeep, remove } from 'lodash';
 import { hasValue, isEmpty, isNotEmpty, hasValueOperator } from '../../shared/empty.util';
 import { CacheableObject } from '../cache/object-cache.reducer';
@@ -110,24 +110,19 @@ export class RequestService {
    * Retrieve a RequestEntry based on their uuid
    */
   getByUUID(uuid: string): Observable<RequestEntry> {
-    return observableRace(
+    return observableCombineLatest([
       this.store.pipe(
-        select(entryFromUUIDSelector(uuid)),
-        hasValueOperator()
+        select(entryFromUUIDSelector(uuid))
       ),
       this.store.pipe(
         select(originalRequestUUIDFromRequestUUIDSelector(uuid)),
         switchMap((originalUUID) => {
-            if (hasValue(originalUUID)) {
               return this.store.pipe(select(entryFromUUIDSelector(originalUUID)))
-            } else {
-              return []
-            }
           },
         ),
-        hasValueOperator()
-      )
-    ).pipe(
+      ),
+    ]).pipe(
+      map((entries: RequestEntry[]) => entries.find((entry: RequestEntry) => hasValue(entry))),
       map((entry: RequestEntry) => {
         // Headers break after being retrieved from the store (because of lazy initialization)
         // Combining them with a new object fixes this issue