The MobX React devtools can be used to analyze when and why React components are re-rendered. They offer three features: 1) visualize when components re-render, 2) show the dependency tree of a component, to see which data it's rendering depends upon, and 3) log in detail which data is changed by your actions, and how these changes propagate through the application.
Applications are driven by state. Many things, like the user interface, should always be consistent with that state.
MobX is a general purpose FRP library that provides the means to derive, for example, a React based user interface automatically from the state and keep it synchronized.
The net result of this approach is that writing applications becomes really straight-forward and boilerplate free.