MobX is designed to enable building web applications with a complex data model in an intuitive and very performant manner. Using React and MobX is currently the simplest way to build component based web applications.

"Half the code, twice the fun" is how people describe MobX, or "So simple, I cannot believe it just works". 



Applications are driven by state. Many things, like the user interface, should always be consistent with that state.
[MobX](https://mobxjs.github.io/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.

Sync the UI with the app state using MobX observable and observer in React

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.

Analyze React components with MobX-React devtools

Derivations form the backbone of MobX and come in two flavors: computed values are values that can be derived from the state automatically. And reactions can be used to manage side effects, such as drawing the user interface. In this lesson you will learn how these concepts relate to each other and how they are optimized automatically by MobX.

Derive computed values and manage side effects with MobX reactions

So far we have used the observable decorator extensively. Let's take a closer look on what it does and see how the extendObservable and observable functions can be used to create observable objects, arrays and maps.

Use observable objects, arrays, and maps to store state in MobX

This lesson explains how actions can be used to control and modify the state of your application. They help you to structure your code base and integrate well with the MobX React Devtools. Actions automatically create transactions, which group changes together.

Use MobX actions to change and guard state

This lesson explains how you can build larger trees of react component and how they are managed efficiently by MobX. You will learn how to pass observable data structures around in props and how the Devtools can be used to analyze the performance of your UI.

Pass observable data through props in MobX

In this lesson we will finally do something useful with our temperatures. We extend it into a small app in which users can enter a location, which is used as input for an external API to fetch weather data. In the mean time MobX keeps our UI in sync with the current state of the request.

Handle user input and asynchronous actions with MobX

Passing down stores through each layer of components can be a tedious job. This lesson demonstrates how Provider can be used to automatically connect observer based components to stores, by leveraging React's context mechanism in the background.

Connect MobX observer components to the store with the React Provider

So far we have been talking briefly about reactions. In this lesson you will learn how reactions can be used to observe state until some condition is met. After that you will see how autorun can be used to automatically trigger side effects. This is used internally by observer as well. We will test this by replacing React with our own handcrafted rendering which is still kept in sync with the state by MobX!

Manage Complex State in React Apps with MobX

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