In React, a hook is a function that allows you to “hook into” React features. Hooks are a way to use state and other React features without writing a class.
There are several built-in hooks in React, including:
Here is a list of all the built-in hooks in React:
useState
: This hook allows you to add state to functional components. It returns an array with two elements: the current state value and a function to update it.
useEffect
: This hook allows you to perform side effects in functional components. It is called after the component renders and can be used to fetch data, perform updates, and more.
useContext
: This hook allows you to access the context object from a functional component. The context object is created using the React.createContext
function.
useReducer
: This hook is similar to useState
, but it allows you to use a reducer function to update the state. It is useful for managing complex state updates.
useCallback
: This hook returns a memoized callback function. It is useful for optimizing performance by avoiding unnecessary re-renders.
useMemo
: This hook returns a memoized value. It is useful for optimizing performance by avoiding unnecessary re-computations.
useRef
: This hook creates a mutable ref object. It is useful for accessing DOM elements or for storing values that don’t need to trigger a re-render when they change.
useImperativeHandle
: This hook allows you to customize the instance value that is exposed to parent components when using ref
. It is useful for implementing advanced patterns like exposing imperative input focus to parent components.
useLayoutEffect
: This hook is similar to useEffect
, but it fires synchronously after all DOM mutations. It is useful for performing DOM mutations that need to happen before the browser paints.
useDebugValue
: This hook can be used to display a label for a custom hook in the React DevTools. It is useful for debugging and for providing a better developer experience.
You can also create your own custom hooks to share logic between components. Custom hooks are simply functions that follow a certain naming convention and can call other hooks.