Issue : rewrite class components into functional components with Hooks

[Thanmaya-Dev]

The issue is a developer wants to update their codebase to a more modern and maintainable standard by refactoring legacy class components into functional components with Hooks, but they're unsure how to handle complex lifecycle methods and state management without the old class-based patterns.

This is a very common task in large codebases. The process involves:

Identifying the class components: Finding all class components that need to be refactored.

Mapping lifecycle methods to Hooks:

componentDidMount -> useEffect with an empty dependency array []

componentDidUpdate -> useEffect with a dependency array containing the state/props to watch

componentWillUnmount -> The return function of a useEffect Hook

Refactoring state: Replacing this.state with useState and this.setState with the corresponding state updater functions (setSomething).

Handling this and methods: Converting class methods into simple functions within the component. this is no longer needed.

This refactoring process modernizes the code, makes it more reusable, and prepares it for future updates in the React ecosystem

[Waseemkhan09]

Thanks for raising this! Refactoring legacy class components into modern functional components with Hooks is a great way to improve maintainability and future-proof your codebase. Here's a step-by-step approach to handle the transition, especially for complex lifecycle and state management scenarios:

1. Identify Class Components

• Use search tools or ESLint plugins to find all class components in the codebase.
• Prioritize based on complexity or frequency of updates.

2. Map Lifecycle Methods to Hooks

Class Lifecycle Method	Functional Component Hook Equivalent
componentDidMount	useEffect(() => { /* mount logic */ }, [])
componentDidUpdate	useEffect(() => { /* update logic */ }, [dependencies])
componentWillUnmount	Cleanup function inside useEffect
	useEffect(() => { return () => { /* cleanup */ } }, [])

3. Refactor State Management

• Replace this.state with useState hooks:

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

• Replace this.setState with the state updater functions:

setState(newState);

### 4. Convert Methods and Bindings
-Move class methods into plain functions inside the component body.
-Since there is no this context in functional components, just call functions directly.
-For event handlers, define functions inline or use useCallback for memoization if needed.

### 5, Additional Tips
-for side effects that depend on props or state, specify the right dependencies array to avoid unwanted re-renders.
-Use useRef to persist values across renders without causing updates.
-Consider breaking down very large components into smaller functional components for better readability and testability.