About the removal of componentWillReceiveProps: you should be able to handle its uses with a combination of getDerivedStateFromProps and componentDidUpdate, see the React blog post for example migrations. And yes, the object returned by getDerivedStateFromProps updates the state similarly to an object passed to setState.
In case you really need the old value of a prop, you can always cache it in your state with something like this:
state = {
cachedSomeProp: null
// ... rest of initial state
};
static getDerivedStateFromProps(nextProps, prevState) {
// do things with nextProps.someProp and prevState.cachedSomeProp
return {
cachedSomeProp: nextProps.someProp,
// ... other derived state properties
};
}
Anything that doesn’t affect the state can be put in componentDidUpdate, and there’s even a getSnapshotBeforeUpdate for very low-level stuff.
UPDATE: To get a feel for the new (and old) lifecycle methods, the react-lifecycle-visualizer package may be helpful.