[PM-14161] Add getById and getByIds rjxs helpers (#11742)

libs/common/src/platform/misc/rxjs-operators.spec.ts

@@ -0,0 +1,58 @@
+import { firstValueFrom, of } from "rxjs";
+
+import { getById, getByIds } from "./rxjs-operators";
+
+describe("custom rxjs operators", () => {
+  describe("getById", () => {
+    it("returns an object with a matching id", async () => {
+      const obs = of([
+        {
+          id: 1,
+          data: "one",
+        },
+        {
+          id: 2,
+          data: "two",
+        },
+        {
+          id: 3,
+          data: "three",
+        },
+      ]).pipe(getById(2));
+
+      const result = await firstValueFrom(obs);
+
+      expect(result).toEqual({ id: 2, data: "two" });
+    });
+  });
+
+  describe("getByIds", () => {
+    it("returns an array of objects with matching ids", async () => {
+      const obs = of([
+        {
+          id: 1,
+          data: "one",
+        },
+        {
+          id: 2,
+          data: "two",
+        },
+        {
+          id: 3,
+          data: "three",
+        },
+        {
+          id: 4,
+          data: "four",
+        },
+      ]).pipe(getByIds([2, 3]));
+
+      const result = await firstValueFrom(obs);
+
+      expect(result).toEqual([
+        { id: 2, data: "two" },
+        { id: 3, data: "three" },
+      ]);
+    });
+  });
+});