If you go to the Portals documentation ( https://facebook.github.io/react/docs/portals.html ) you can find some examples throughout.

Both of the CodePen example links on that page are insidiously broken. The demos appear to work, but they don't actually demonstrate the claimed portal functionality at all:

    // These two containers are siblings in the DOM
    const appContainer = document.getElementById('app-container');
    const modalContainer = document.getElementById('app-container');

Note that both variables refer to the same element.

Sorry, there was so much to do in the release that some issues crept into the new docs. We'll fix them soon. :-)

Fixed now! Thanks for the bug report!

No problem! And on re-reading my comment, I probably shouldn't have used the word "insidiously", it came off a lot more negative than I intended. Thanks for the quick fix.