[PM-14416] Improve null value filtering for task service

libs/vault/src/tasks/services/default-task.service.ts

@@ -1,5 +1,5 @@
 import { Injectable } from "@angular/core";
-import { filter, map, switchMap } from "rxjs";
+import { map, switchMap } from "rxjs";
 
 import { ApiService } from "@bitwarden/common/abstractions/api.service";
 import { OrganizationService } from "@bitwarden/common/admin-console/abstractions/organization/organization.service.abstraction";
@@ -8,7 +8,7 @@ import { StateProvider } from "@bitwarden/common/platform/state";
 import { SecurityTaskId, UserId } from "@bitwarden/common/types/guid";
 import { SecurityTask, SecurityTaskStatus, TaskService } from "@bitwarden/vault";
 
-import { perUserCache$ } from "../../utils/observable-utilities";
+import { filterOutNullish, perUserCache$ } from "../../utils/observable-utilities";
 import { SecurityTaskData } from "../models/security-task.data";
 import { SecurityTaskResponse } from "../models/security-task.response";
 import { SECURITY_TASKS } from "../state/security-task.state";
@@ -35,7 +35,7 @@ export class DefaultTaskService implements TaskService {
         }
         return tasks;
       }),
-      filter((tasks) => tasks != null),
+      filterOutNullish(),
       map((tasks) => tasks.map((t) => new SecurityTask(t))),
     );
   });

libs/vault/src/utils/observable-utilities.ts

@@ -1,4 +1,4 @@
-import { Observable, shareReplay } from "rxjs";
+import { filter, Observable, OperatorFunction, shareReplay } from "rxjs";
 
 import { UserId } from "@bitwarden/common/types/guid";
 
@@ -20,3 +20,18 @@ export function perUserCache$<TValue>(
     return observable;
   };
 }
+
+/**
+ * Strongly typed observable operator that filters out null/undefined values and adjusts the return type to
+ * be non-nullable.
+ *
+ * @example
+ * ```ts
+ * const source$ = of(1, null, 2, undefined, 3);
+ * source$.pipe(filterOutNullish()).subscribe(console.log);
+ * // Output: 1, 2, 3
+ * ```
+ */
+export function filterOutNullish<T>(): OperatorFunction<T | undefined | null, T> {
+  return filter((v): v is T => v != null);
+}