Book Image

MobX Quick Start Guide

By : Pavan Podila, Michel Weststrate
Book Image

MobX Quick Start Guide

By: Pavan Podila, Michel Weststrate

Overview of this book

MobX is a simple and highly scalable state management library in JavaScript. Its abstractions can help you manage state in small to extremely large applications. However, if you are just starting out, it is essential to have a guide that can help you take the first steps. This book aims to be that guide that will equip you with the skills needed to use MobX and effectively handle the state management aspects of your application. You will first learn about observables, actions, and reactions: the core concepts of MobX. To see how MobX really shines and simplifies state management, you'll work through some real-world use cases. Building on these core concepts and use cases, you will learn about advanced MobX, its APIs, and libraries that extend MobX. By the end of this book, you will not only have a solid conceptual understanding of MobX, but also practical experience. You will gain the confidence to tackle many of the common state management problems in your own projects.
Table of Contents (17 chapters)
Title Page
Packt Upsell


Reactions can really change the world for your app. They are the side-effect causing behaviors that react to the changes in observables. Reactions complete the core triad of MobX and act as the observers of the observables. Take a look at this diagram:

MobX gives you three different ways to express your reactions or side-effects. These are autorun(), reaction(), and when(). Let's see each of these in turn.


autorun() is a long-running side-effect that takes in a function (effect-function) as its argument. The effect-function function is where you apply all your side-effects. Now, these side-effects may depend on one or more observables. MobX will automatically keep track of any change happening to these dependent observables and re-execute this function to apply the side-effect. It's easier to see this in code, as shown here: 

import { observable, action, autorun } from 'mobx';

class Cart {
@observable modified = new Date();
@observable.shallow items = [];