react-component-example.js

class UserList extends React.Component {
  constructor () {
    super();
    this.state = {
      users: []
    };
  }

  componentDidMount () {
    fetch('/users').then(users => {
      this.setState({ users });
    });
  }

  render () {
    return (
      <ul>
        {this.state.users.map(user => <li key={user.id}>{user.name}</li>)}
      </ul>
    );
  }
}