react_component_in_action.js

const e = React.createElement;
class FollowButton extends React.Component {
  constructor(props) {
    super(pros);
    this.state = { follow: false };
  }
  render() {
    if (this.state.follow) {
      return 'You are following this.';
    }
    //create like button
    return e(
      'button',
      { onClick: () => this.setState({ follow: true }) },
      'Follow'
    );
  }
}