React as a UI Runtime

It’s the API that lets us tell React to render a particular React element tree inside a container host instance. React will look at the (in our example, ) and ask the React DOM renderer to create a host instance for it and set the properties:

In our example, effectively React will do this:

If the React element has child elements in , React will recursively create host instances for them too on the first render. The React element may be different every time, but when does it refer to the same host instance conceptually?

Source: overreacted.io