mobx and mobx-react are two NPM packages that are used extensively to build the Reactive UI. The mobx package provides the API to build the observable state, actions, and reactions. On the other hand, mobx-react gives the binding glue to connect the React components to the observable state and also react to any changes. In our example, we made use of these APIs to build a book search app. When creating your observer-driven component tree, make sure to go granular with the use of observers. This way you will react to just the observables you need to render the UI.
The SearchTextField, SearchStatus, and ResultsList components were created with the intent of being granular and reacting to a focused observable surface. This is the recommended way to use MobX with React.
In the next chapter we will dive deeper into MobX, with an exploration of the Observables...
