HelloWorld.js

import React from 'react';

class HelloWorld extends React.Component {
  constructor(props) {
    super(props);
  }

  sayHi(event) {
    alert(`Hi ${this.props.name}`);
  }

  render() {
    return (
      <div>
        <a href="#" onClick={this.sayHi.bind(this)}>Say Hi</a>
      </div>
    );
  }
}

HelloWorld.propTypes = {
  name: React.PropTypes.string.isRequired
};

export default HelloWorld;