Stateful components and life cycle methods

React components can manage their own state and update only when the state has changed. Stateful React components are written using ES6 classes:

class Example extends React.Component { 
   render() { 
      <span>This is an example</span> 
   } 
} 

React class components have a state instance property to access their internal state and a props property to access properties passed to the component:

class Example extends React.Component {  
    state = { title: null } 
    render() { 
        return ( 
            <React.Fragment>  
                <span>{this.props.title}</span>  
                <span>{this.state.title}</span>  
            </React.Fragment>  
        ) 
    } 
} 

And their state can be mutated by using the setState instance method:

class Example extends React.Component...