How to share state between components?

Sharing state between components in React is a fundamental aspect of building dynamic applications. As components are the building blocks of a React application, effectively managing and distributing state ensures components reflect the most accurate data and improve user experience.

1. Parent-Child Relationship: The most straightforward way to share state is through props. If a parent component holds the state, it can pass that state down to its children via props. Any changes to the state in the parent component will automatically reflect in the child components receiving the state as props.

2. Lifting State Up: In scenarios where sibling components need to share state, it’s often recommended to lift the state up to their closest common ancestor. This means that the shared state resides in the parent, and both siblings can access and modify it through props or callback functions.

3. Context API: For application-wide state or when multiple component levels are involved, prop-drilling (passing props through intermediate components) becomes cumbersome. React’s Context API provides a way to share values (state) between components without having to explicitly pass props at every level. With a combination of `React.createContext` and the `useContext` hook, components can subscribe to context changes and access shared state seamlessly.

4. State Management Libraries: In larger applications with more complex state logic, external state management solutions like Redux or MobX can be employed. These libraries provide more advanced mechanisms to maintain, update, and share state across multiple components, bringing structure and predictability to state changes.

5. Hooks and Custom Hooks: With the introduction of React hooks, sharing state logic has become even more flexible. Using hooks like `useState` and `useReducer`, components can maintain their own state. Moreover, with custom hooks, it’s possible to extract component logic, including state management, and reuse it across different components.

The method you choose to share state largely depends on the size and complexity of your application. While props and lifting state up are sufficient for smaller applications, the Context API, custom hooks, or external libraries might be more suitable for larger, more intricate applications.