Steps to reproduce:
$ create-react-app my-app
then copy the React example inside the App.js file,
uncomment ReactDOM.render(<Button />, mountNode),
instead trying to put <Button /> directly inside the JSX.
Complained about undefined html, so I had added this line:
var html = require('bel')
The error changed to
assert.js:59Uncaught AssertionError: nanocomponent-adapters/react: component should be type function
in the console and the screen is empty.