Questions
19 of 22
1What is RTK Query and why was it introduced?
2How is RTK Query different from createAsyncThunk?
3What problem does RTK Query solve compared to traditional data fetching with Redux?
4What are the two main APIs in RTK Query? (createApi and fetchBaseQuery)
5How do you define an API slice using createApi()?
6What’s the purpose of reducerPath in createApi()?
7What are endpoints in RTK Query?
8What’s the difference between query and mutation endpoints in RTK Query?
9How do you use auto-generated hooks from RTK Query (e.g., useGetPostsQuery)?
10How do you refetch data manually in RTK Query?
11How do you handle caching and invalidation in RTK Query?
12What are tags and how do they help in cache invalidation?
13How can you invalidate cache for specific queries?
14How do you customize request headers or authentication tokens in RTK Query?
15How do you handle request errors or loading states?
16How can RTK Query work with GraphQL or custom fetch logic?
17How does RTK Query handle deduplication of requests?
18How can you integrate RTK Query with server-side rendering (SSR)?
19How do you perform optimistic updates in RTK Query?
20How can you manually update the cache using updateQueryData?
21How do you reset or clear RTK Query cache programmatically?
22What are best practices for structuring RTK Query API slices in large apps?
RTKRTK
Basics
Slice
Actions
Reducers
RTK Query
Store
Thunk
Scenario Based
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How do you perform optimistic updates in RTK Query?

Optimistic updates in RTK Query allow you to immediately reflect a change in the UI before the server confirms it. This provides a smoother user experience by making the app feel more responsive.

Steps to Implement Optimistic Updates
  1. 1

    1. Use onQueryStarted: Handle side effects when a mutation is triggered.

  2. 2

    2. Apply Temporary Cache Updates: Use updateQueryData to optimistically update cached data.

  3. 3

    3. Revert on Failure: If the mutation fails, use the rollback function to undo changes.

Example: Optimistic Update with RTK Query

In this example, the UI is immediately updated when a post is modified. If the server responds with an error, RTK Query automatically rolls back to the previous state.

Benefits of Optimistic Updates
  1. 1

    - Enhanced User Experience: Changes appear instantaneously in the UI.

  2. 2

    - Reduced Perceived Latency: The app feels faster and more responsive.

  3. 3

    - Built-in Rollback: Safe recovery from failed updates with minimal effort.

Optimistic updates make your RTK Query app more interactive while maintaining consistency between client and server data.