HelloWorld.js

import React from 'react';

const HelloWorld = (props) => {
  const sayHi = (event) => {
    alert(`Hi ${props.name}`);
  };

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

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

export default HelloWorld;