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useAppSelector

The useAppSelector hook is a custom hook that is often used in Redux Toolkit-based applications to replace the standard useSelector hook from the react-redux library. The purpose of this custom hook is to provide type safety for the Redux store's state when using TypeScript.

Here's a typical definition of useAppSelector:

import { TypedUseSelectorHook, useSelector } from "react-redux";
import { RootState } from "../store"; // Import your RootState type

export const useAppSelector: TypedUseSelectorHook<RootState> = useSelector;

How it Works:​

  1. TypedUseSelectorHook: This is a generic type that takes the type of the root state of your Redux store. It helps in providing type safety when you use the useSelector hook.

  2. useSelector: This is the standard hook from react-redux that allows you to extract data from the Redux store state, using a selector function.

  3. RootState: This is the type of the root state of your Redux store. It's usually defined when you combine your reducers.

By using useAppSelector, you can ensure that the selector functions you write are type-safe and will provide autocompletion and error checking based on the types defined in your Redux store's state.

Usage:​

You would use useAppSelector in the same way you use useSelector. For example:

const someData = useAppSelector((state) => state.someReducer.someData);

This ensures that state.someReducer.someData is type-safe and will give you TypeScript errors if you try to access properties that do not exist on someData.