Although there is a lean outer-level API for MobX, there is also a set of APIs for more fine-grained observation and mutation. We saw how the Object API can be used to make very surgical changes in your observable tree. With observe() and intercept(), you can track the changes happening in an observable and also intercept to modify the change.
spy() and trace() are your friends during debugging, and coupled with mobx-react-devtools, you have a visual debugger for identifying and improving render performance. These tools and utilities give you a rich Developer eXperience (DX) when working with MobX.
In Chapter 8, Exploring mobx-utils and mobx-state-tree, we will raise the bar on using MobX with the special packages mobx-utils and mobx-state-tree.