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Introduction to Redux
Introduction to Redux
2. Fundamental Concepts
Rules for Reducers
There are certain rules while using Redux Reducers which we need to follow to avoid certain bugs or surprises.
- Reducers should use only the
state
andaction
arguments to calculate the new state. They shouldn't access any external values; - Reducers must not perform asynchronous logic or side effects such as making API calls or running timers etc.;
- The state should not be directly modified inside the reducer functions, instead, the reducer function should return a duplicate state object with updated values. This rule only applies when creating reducers manually. If we use
createSlice
to create a slice, we can modify thestate
directly.
It is important to note that in the case of createSlice
reducers, we directly modify the state object, however, in the backend, Redux creates a new duplicate object and assigns it the new changes, so the rule is being followed, but in the backend.
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