The render prop pattern recently became a popular replacement for the child as function pattern.
Previously the render prop on react-intersection-observer, was handled differently from children so it only rendered when the element was inside the viewport.
⚠️ Breaking change
If you were using the render prop before, you need to handle when to render the content.
Old way
<Observer render={() => <div>Only rendered when in viewport</div>} />New way
<Observer render={inView => inView ? <div>Only rendered when in viewport</div> : null} />