I am using Redux in my React application and I often need to extract values from the Redux store using useSelector. Here are the two approaches I have considered:
Approach 1: Selecting individual state properties:
const username = useSelector((state) => state.user.username);
const userCart = useSelector((state) => state.user.cart);
Approach 2: Selecting the whole state and destructuring:
const { username, cart } = useSelector((state) => state.user);
I am concerned about the performance implications of these two approaches. Specifically, I am trying to understand:
If I change an unrelated state property (e.g.,
phoneNumber
) in theuser
slice, will my component re-render in either or both approaches?Which approach is more suitable for optimal performance in terms of minimizing unnecessary re-renders?
Here is an example of my Redux slice:
const initialState = {
username: '',
cart: [],
phoneNumber: '',
address: ''
};
const userSlice = createSlice({
name: 'user',
initialState,
reducers: {
// reducers here
}
});
I expect that:
- Using the first approach (selecting individual properties) will minimize unnecessary re-renders, as the component should only re-render if
username
orcart
changes. - Using the second approach (destructuring the state) might cause unnecessary re-renders if any property in the
user
slice changes, even if the component does not use that property.
I read in the Redux documentation that Redux re-renders the component if the previous state is different from the current state, but I am unsure how this works in practice with the above approaches.
I am aware of libraries like reselect which are used to optimize state selection, but I do not want to consider them in this context.
Can someone please clarify the performance implications of these two approaches and recommend the best practice for extracting state from the Redux store?