freeCodeCamp/guide/english/react/component/index.md

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---
title: React - Components
---
## React - Components
Components are reusable in react.js. You can inject value into props as given below :
```jsx
function Welcome(props) {
return <h1>Hello, {props.name}</h1>;
}
const element = <Welcome name="Faisal Arkan" />;
ReactDOM.render(
element,
document.getElementById('root')
);
```
The value ```name="Faisal Arkan"``` will be assigned to ```{props.name}``` from ```function Welcome(props)``` and returns a component ```<h1>Hello, Faisal Arkan</h1>``` which is saved into the const variable ```element```. The component can then be rendered via ```ReactDOM.render(element, document.getElementById('root'));```. ```document.getElementById('root')``` in this case is the target location you would like the ```element``` component to be rendered.
### Other ways to declare components
There are many ways to declare components when using React.js, but there are two kinds of components, ***stateless*** components and ***stateful*** components.
### Stateful
#### Class Type Components
```jsx
class Cat extends React.Component {
constructor(props) {
super(props);
this.state = {
humor: 'happy'
}
}
render() {
return(
<div>
<h1>{this.props.name}</h1>
<p>
{this.props.color}
</p>
</div>
);
}
}
```
### Stateless Components
#### Functional Components (Arrow Function from ES6)
```jsx
const Cat = props => {
return (
<div>
<h1>{props.name}</h1>
<p>{props.color}</p>
</div>;
);
};
```
#### Implicit Return Components
```jsx
const Cat = props =>
<div>
<h1>{props.name}</h1>
<p>{props.color}</p>
</div>;
```