Hooks allow functions to have access to state and other React features without using classes.
They provide a more direct API to React concepts like props, state, context, refs, and lifecycle.
What is a Hook?
Hooks are functions that let you "hook into" React state and lifecycle features from functional components.
Example
Here is an example of a Hook. Don't worry if it doesn't make sense. We will go into more detail later in this lesson .
import { useState } from 'react';
import { createRoot } from 'react-dom/client';
function FavoriteColor() {
const [color, setColor] = useState("red");
return ( <> <h1>My favorite color is {color}!</h1> <button
type="button"
onClick={() => setColor("blue")}
>Blue</button> <button
type="button"
onClick={() => setColor("red")}
>Red</button> <button
type="button"
onClick={() => setColor("pink")}
>Pink</button> <button
type="button"
onClick={() => setColor("green")}
>Green</button> </> );
}
createRoot(document.getElementById('root')).render( <FavoriteColor /> );You must import Hooks from react .
Here we are using the useState Hook to keep track of the application state.
State generally refers to application data or properties that need to be tracked.
Hook Rules
There are 3 rules for hooks
- Hooks can only be called inside React function components.
- Hooks can only be called at the top level of a component.
- Hooks cannot be conditional
Note
Hooks will not work in React class components.
Custom Hooks
If you have stateful logic that needs to be reused in several components, you can build your own custom Hooks.
We'll go into more detail in the Custom Hooks section .