React Hook “useState” is called in function “app” which is neither a React function component or a custom React Hook function

React Hook “useState” is called in function “app” which is neither a React function component or a custom React Hook function

When working with React, it is important to understand the rules and best practices for using hooks. One common issue that developers may encounter is the error message “React Hook ‘useState’ is called in function ‘app’ which is neither a React function component or a custom React Hook function”. This error occurs when the useState hook is not used within a valid React component or custom hook.

To resolve this issue, there are two possible solutions:

Solution 1: Convert the function into a React function component

If the function “app” is not already a React function component, you can convert it into one. React function components are the primary way to define components in React and are required for using hooks.

Here’s an example of how you can convert the “app” function into a React function component:

import React, { useState } from 'react';

const App = () => {
  const [state, setState] = useState(initialState);

  // Rest of your component code

  return (
    // JSX for your component
  );
}

export default App;

Make sure to replace “initialState” with the initial state value you want to use.

Solution 2: Extract the logic into a custom React Hook function

If the function “app” contains reusable logic that doesn’t belong to a specific component, you can extract that logic into a custom React Hook function. Custom hooks are JavaScript functions that start with the word “use” and can call other hooks if needed.

Here’s an example of how you can extract the logic into a custom React Hook function:

import { useState } from 'react';

const useCustomHook = () => {
  const [state, setState] = useState(initialState);

  // Rest of your custom hook logic

  return [state, setState];
}

export default useCustomHook;

Make sure to replace “initialState” with the initial state value you want to use.

Then, you can use the custom hook in your “app” function or any other React function component:

import React from 'react';
import useCustomHook from './useCustomHook';

const App = () => {
  const [state, setState] = useCustomHook();

  // Rest of your component code

  return (
    // JSX for your component
  );
}

export default App;

By following these solutions, you can ensure that the useState hook is used correctly within a valid React function component or a custom React Hook function, resolving the error message.

Remember to always follow the guidelines and best practices provided by the React documentation when working with hooks.

Happy coding!