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What Are React Hooks?

2 minutes read

React hooks are functions that allow developers to use state and other React features in functional components. They were introduced in React version 16.8 as a way to add state and lifecycle methods to functional components, which could previously only be done with class components. Hooks are a more intuitive and flexible way to manage state and side effects in React applications. Some popular React hooks include useState, useEffect, useContext, and useRef. By using hooks, developers can write cleaner and more modular code, leading to a more efficient and maintainable React application.


What is the useCallback hook used for in React?

The useCallback hook in React is used to memoize functions. This means that it returns a memoized version of the callback function that only changes if one of the dependencies has changed. This can help improve performance by preventing unnecessary re-renders of components that depend on the callback function.


How to manage global state in React using custom hooks?

  1. Create a custom hook: To manage global state in React using custom hooks, you can create a custom hook that will contain the logic to manage your global state. You can create this hook by following the usual rules for creating a custom hook in React.
  2. Use context: To share data across your application, you can use the context API provided by React. Create a context and provide the state and the functions to update the state using the useContext and useReducer hooks.
  3. Initialize state: Use the useState hook to initialize the state in your custom hook. You can also use useReducer for more complex state management.
  4. Update state: Create functions inside your custom hook that will update the state. These functions can be passed down to your components so they can update the global state.
  5. Use the custom hook in your components: Import and use your custom hook in your components where you need to access the global state. You can use the state and the functions provided by the custom hook to interact with the global state in your components.


By following these steps, you can effectively manage global state in React using custom hooks. This approach can help you keep your code organized and maintainable as your application grows.


What is the effect cleanup function in React hooks?

The cleanup function in React hooks is used to perform clean up operations when the component using the hook is unmounted or before it re-renders. This allows you to free up resources, cancel ongoing operations, or generally tidy up any side effects that were created by the hook during its lifecycle.


In some cases, the cleanup function is also used to prevent memory leaks or unwanted behavior caused by lingering effects. It helps ensure that the component remains in a stable and consistent state throughout its lifecycle.

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