[PM-6654] new app id service for angular (#8229)

* Improve state documentation

* Add namespace for application id

* Spec out behavior of app id service

* Use state providers for app ids

* Migrate app Id

* Add reactive interface

libs/common/src/platform/services/app-id.service.spec.ts

@@ -0,0 +1,101 @@
+import { FakeGlobalStateProvider } from "../../../spec";
+import { Utils } from "../misc/utils";
+
+import { ANONYMOUS_APP_ID_KEY, APP_ID_KEY, AppIdService } from "./app-id.service";
+
+describe("AppIdService", () => {
+  const globalStateProvider = new FakeGlobalStateProvider();
+  const appIdState = globalStateProvider.getFake(APP_ID_KEY);
+  const anonymousAppIdState = globalStateProvider.getFake(ANONYMOUS_APP_ID_KEY);
+  let sut: AppIdService;
+
+  beforeEach(() => {
+    sut = new AppIdService(globalStateProvider);
+  });
+
+  afterEach(() => {
+    jest.resetAllMocks();
+  });
+
+  describe("getAppId", () => {
+    it("returns the existing appId when it exists", async () => {
+      appIdState.stateSubject.next("existingAppId");
+
+      const appId = await sut.getAppId();
+
+      expect(appId).toBe("existingAppId");
+    });
+
+    it.each([null, undefined])(
+      "uses the util function to create a new id when it AppId does not exist",
+      async (value) => {
+        appIdState.stateSubject.next(value);
+        const spy = jest.spyOn(Utils, "newGuid");
+
+        await sut.getAppId();
+
+        expect(spy).toHaveBeenCalledTimes(1);
+      },
+    );
+
+    it.each([null, undefined])("returns a new appId when it does not exist", async (value) => {
+      appIdState.stateSubject.next(value);
+
+      const appId = await sut.getAppId();
+
+      expect(appId).toMatch(Utils.guidRegex);
+    });
+
+    it.each([null, undefined])(
+      "stores the new guid when it an existing one is not found",
+      async (value) => {
+        appIdState.stateSubject.next(value);
+
+        const appId = await sut.getAppId();
+
+        expect(appIdState.nextMock).toHaveBeenCalledWith(appId);
+      },
+    );
+  });
+
+  describe("getAnonymousAppId", () => {
+    it("returns the existing appId when it exists", async () => {
+      anonymousAppIdState.stateSubject.next("existingAppId");
+
+      const appId = await sut.getAnonymousAppId();
+
+      expect(appId).toBe("existingAppId");
+    });
+
+    it.each([null, undefined])(
+      "uses the util function to create a new id when it AppId does not exist",
+      async (value) => {
+        anonymousAppIdState.stateSubject.next(value);
+        const spy = jest.spyOn(Utils, "newGuid");
+
+        await sut.getAnonymousAppId();
+
+        expect(spy).toHaveBeenCalledTimes(1);
+      },
+    );
+
+    it.each([null, undefined])("returns a new appId when it does not exist", async (value) => {
+      anonymousAppIdState.stateSubject.next(value);
+
+      const appId = await sut.getAnonymousAppId();
+
+      expect(appId).toMatch(Utils.guidRegex);
+    });
+
+    it.each([null, undefined])(
+      "stores the new guid when it an existing one is not found",
+      async (value) => {
+        anonymousAppIdState.stateSubject.next(value);
+
+        const appId = await sut.getAnonymousAppId();
+
+        expect(anonymousAppIdState.nextMock).toHaveBeenCalledWith(appId);
+      },
+    );
+  });
+});