From ReactJS wiki page about Virtual DOM:
React creates an in-memory data structure cache, computes the resulting differences, and then updates the
I don't know if this is the answer to your question but I found this in the the official React docs:
React builds and maintains an internal representation of the rendered UI. It includes the React elements you return from your components. This representation lets React avoid creating DOM nodes and accessing existing ones beyond necessity, as that can be slower than operations on JavaScript objects. Sometimes it is referred to as a "virtual DOM", but it works the same way on React Native.
So I would say that yes, it manages a very similar internal representation to the one used in React.js. Then I guess that it uses Javascript APIs to render native views just like the article you read suggests.
EDIT This post provided by Sebas in a comment is also interesting because a member of the React (and React Native) team says that:
React Native shows that ReactJS has always been more about "zero DOM" than "virtual DOM" (contrary to popular belief).
It seems like the so-called 'React virtual DOM' is much closer to an internal structure/representation of the elements that can be mapped to various technologies than to a HTML DOM.