Experiment: TanStack Query #39
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| - `localization/` - Things related to user locale | ||
| - `navigation/` - Navigators, routes | ||
| - `redux/` - Actions, reducers, sagas | ||
| - `remote/` - Remote state (via TanStack Query) |
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This indicates remote state (server state) in terms of reflecting inside the app what's stored on some remote server (backend). It's keeping networking state - loading, errors and data from requests and responses.
It's different than redux/, which is client local state, that doesn't need to by synchronised with server. It's updated by local user's action or some effects from remote state updates.
This structure allows to keep them separate.
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| const DemoScreen = ({ navigation }: DemoScreenProps) => { | ||
| const [isLogoutLoading, setIsLogoutLoading] = useState(false) |
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loading state is handled by TanStack query, see useLatestComicQuery. We don't have to implement our own state here. State of query will be the same (cached) if we call query with the same id from another component.
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| useEffect(() => { | ||
| if (isNotRequested(comicRequest)) { | ||
| dispatch(getLatestComicAsync()) |
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No need to explicitly call initial fetch. It's handled by default by TanStack Query inside useLatestComicQuery
| persistor.pause() | ||
| await clearPersistence() | ||
| dispatch(resetStore()) | ||
| persistor.persist() |
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Cleanup logic moved to useLogOutMutation, which is in template/src/remote/auth.ts.
Also, no need to set loading states, because it's handled internally by lib.
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| getLatestComicAsyncFailure: (state, action: PayloadAction<Error['message']>) => { | ||
| state.comic = Failure(action.payload) | ||
| }, |
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This boilerplate of 3 actions for calling request and receiving success/failure was replaced by useQuery.
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| interface DemoState { | ||
| counter: number | ||
| comic: RemoteData<Comic, Error['message']> |
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No need to store RemoteData values (errors, loading) in our local state, because it's stored internally by useQuery in it's state that represents server state. This way networking doesn't mix with local state (MST or redux).
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| export function* watchGetLatestComicSaga() { | ||
| yield* takeEvery(getLatestComicAsync, fetchLatestComic) |
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sagas logic was replaced by useQuery in useLatestComicQuery
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| export enum RemoteDataStates { | |||
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The whole logic from api.ts file, with RemoteData, was replaced by useQuery and useMutation. This logic is in TanStack Query library.
| expect(result.counter).toEqual(410) | ||
| }) | ||
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| it('set getLatestComicAsync to Loading if there is no comic in store', () => { |
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This test is removed, because it's testing switching to Loading state when request is started. It's handled by lib now, which is tested separately (in lib).
see isLoading for query: https://tanstack.com/query/v5/docs/react/reference/useQuery
or isPending for mutation: https://tanstack.com/query/v5/docs/react/reference/useMutation
| expect(result.comic).toEqual(Loading) | ||
| }) | ||
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| it('set getLatestComicAsync to Refreshing if there is already comic in store', () => { |
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This test is removed, because it's testing switching to Refreshing state when request is started while already having data. It's handled by lib now, which is tested separately (in lib).
See isRefetching -> https://tanstack.com/query/v5/docs/react/reference/useQuery
| expect(result.comic).toEqual(Refreshing(comicMockParsed)) | ||
| }) | ||
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| it('set getLatestComicAsyncSuccess state', () => { |
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This test is removed, because it's testing switching to Success state when received successful response. It's handled by lib now, which is tested separately (in lib).
See isSuccess in https://tanstack.com/query/v5/docs/react/reference/useQuery
| expect(result.comic).toEqual(Success(comicMockResponse)) | ||
| }) | ||
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| it('set getLatestComicAsyncFailure state', () => { |
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This test is removed, because it's testing switching to Failure state when received successful response. It's handled by lib now, which is tested separately (in lib).
See isError in https://tanstack.com/query/v5/docs/react/reference/useQuery
| import { decrementCounterBy, demoSlice, incrementCounterBy } from '@screens/demoSlice' | ||
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| describe('DemoSlice', () => { | ||
| describe('Demo saga fetchLatestComic', () => { |
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Tests of fetchLatestComic are replaced by tests of useLatestComicQuery
| } as ReturnType<typeof remoteComics.useLatestComicQuery>) | ||
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| jest.mock('@remote/auth', () => ({ | ||
| useLogOutMutation: jest.fn().mockImplementation(() => ({ |
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Hooks with effects are mocked in component unit tests to avoid unfinished tests (promises running indefinitely).
It's a separate issue that existed here before migration to TanStack Query.
| import { mapComic } from '@api/mappers/comicMappers' | ||
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| export const useLatestComicQuery = () => { | ||
| return useQuery({ |
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This useQuery replaced a lot of boilerplate for fetching the latest comic
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| export const useLatestComicQuery = () => { | ||
| return useQuery({ | ||
| queryKey: ['comic', 'latest'], |
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This key - ['comic', 'latest'] - can be used in another place to get to the same data (cached data, error and loading states)
| payload: { | ||
| tokens: { | ||
| data: fakeAuthTokens, | ||
| type: RemoteDataStates.SUCCESS, |
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no need to store and test request state, because it's implemented and tested in useQuery and useMutation
| describe('#logInAsyncFailure', () => { | ||
| it('should store auth error message', () => { | ||
| const state = authSlice.reducer(initialState, logInAsyncFailure(logInErrorMessage)) | ||
| expect(state.tokens).toEqual(Failure(logInErrorMessage)) |
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Removed those tests because there is no need to test switching states: Loading, Success and Failure, because it's handled by useQuery/useMutation in library
| }) | ||
| }) | ||
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| describe('#watchLogInSaga', () => { |
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Tests of logging in logic are moved to tests of useLogInMutation
Description
It's purpose is a comparison of approaches to networking layer: current one in the project vs using query library.
I left some comments in this PR to help understand those changes.
Changes
Migrated our remote data layer to TanStack Query. Template in this experiment uses
useQueryanduseMutation. Basically it removed all the boilerplate implemented intemplate/src/utils/api.ts.Considerations
TODO:
useLatestComicQuery,useLogInMutation,useLogOutMutation,apisauce(it's related to axios) to also remove our boilerplate fromtemplate/src/api/common.ts.Demo
No demo. It looks the same. 🌝