import React from 'react'

export default class Application extends React.Component {
  render() {
    return (
      <h1>Hello world</h1>
    )
  }
}

import React from 'react'

/**
 * Main Application component
 *
 * @return  {Node}
 */
export default function Application() {
  return (
    <h1>Hello world!</h1>
  )
}

Rewrite Application as pure component
Rewrite Application as pure component

Whatever that actually means...
