Introduction to React Hooks

Hooks are introduced in the React 16.8 version, functions that let you hook into React state and lifecycle features from function components. It allows us to use more of React’s features without classes. They are completely opt-in and backward-compatible.

When should I use a Hook?

If you write a function component and realize you need to add some state to it, previously you had to convert it to a class. Now you can use a Hook inside the existing function component.  If you are looking to implement the latest release, with a React.JS Development Company to leverage its features.

Pros:
1. Better alternative to the common design patterns.
2. Easy to test and maintain (functional components).
3. Create re-usable, isolated functional components to avoid redundant logic.

Rules:
1. Don’t call Hooks inside loops, conditions, or nested functions.
2. Call Hooks from React functional component of custom component

Basic Hooks:

1. useState

useState is a Hook that lets you add React state to function components.

2. useEffect
   Allow us to write actions to be done after render.
   You can think of useEffect Hook as componentDidMount, componentDidUpdate, and componentWillUnmount combined.

3. useContext
   Accepts a context object and returns the current context value for that context.

Additional Hooks:
1. useReducer
    lets you optimize performance for components that trigger deep updates because you can pass dispatch down instead of callbacks.
2. useCallback
    useCallback will return a memoized version of the callback that only changes if one of the dependencies has changed
3. useMemo
    It will only recompute the memoized value when one of the dependencies has changed.
4. useRef
    Can be used for keeping mutable values.
5. useImperativeHandle
    Customizes the instance value that is exposed to parent components when using ref.
6. useLayoutEffect
    For handling synchronous re-rendering of DOM.
7. useDebugValue
    useDebugValue can be used to display a label for custom hooks in React DevTools.

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