SOURCE

function formatName(user) {
  return user.firstName + ' ' + user.lastName;
}
con
const user = {
  firstName: 'Harper',
  lastName: 'Perez'
};

const element = (
  <h1>
    Hello, {formatName(user)}!
  </h1>
);

ReactDOM.render(
  element,
  document.getElementById('root')
);

<script src='https://unpkg.com/react/umd/react.production.min.js'>
</script>
<script src='https://unpkg.com/react-dom/umd/react-dom.production.min.js'>
</script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/antd/3.0.0-alpha.9/antd.js'>
</script>
<div id="root">
</div>