file.js

// vim: syntax=JSX
import React from 'react';

export default class MyClass extends React.Component {
  render() {
    return (
      <a href="google.com">Let's head to google.com</a>
    );
  }
}

file.jsx

import React from 'react';

export default class MyClass extends React.Component {
  render() {
    return (
      <a href="google.com">Let's head to google.com</a>
    );
  }
}