[brianvaughn]

This was implied but not explicitly covered in the blog post. I updated it this morning to be more explicit [1]!

> You may notice in the example above that props.currentRow is mirrored in state (as state.lastRow). This enables getDerivedStateFromProps to access the previous props value in the same way as is done in componentWillReceiveProps.

> You may wonder why we don’t just pass previous props as a parameter to getDerivedStateFromProps. We considered this option when designing the API, but ultimately decided against it for two reasons:

> * A prevProps parameter would be null the first time getDerivedStateFromProps was called (after instantiation), requiring an if-not-null check to be added any time prevProps was accessed.

> * Not passing the previous props to this function is a step toward freeing up memory in future versions of React. (If React does not need to pass previous props to lifecycles, then it does not need to keep the previous props object in memory.)

1: https://reactjs.org/blog/2018/03/27/update-on-async-renderin...