Immutable State
Immutability is a core principle in React and Redux state management, requiring that state should never be directly mutated but instead replaced with new copies whenever it changes.
Why Immutability Matters
React relies on reference comparisons to detect changes efficiently. If you mutate an object directly, React may not detect the change, since the object reference remains the same, leading to UI that fails to update.
Incorrect: Mutating State Directly
Correct: Creating a New Object
Updating Arrays Immutably
Immutability in Redux Reducers
Traditional Redux reducers must always return a new state object rather than mutating the existing state parameter directly.
How Redux Toolkit Simplifies This with Immer
Redux Toolkit uses the Immer library internally, allowing you to write code that appears to mutate state directly inside createSlice reducers, while Immer safely produces an immutable update behind the scenes.
Conclusion
Understanding and correctly applying immutability principles ensures React and Redux can accurately detect state changes, preventing subtle rendering bugs in your React Native application.
