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

Derivations (computed properties)

Derivation is a term that is used quite frequently in the MobX parlance. It is given special emphasis in client-state modeling. As we saw in the previous chapter, the observable state can be determined by the combination of the core-mutable-state and a derived-read-only-state:

Observable State = (Core-mutable-State) + (Derived-readonly-State)

It is essential to keep the core state as lean as possible. This is the part that is expected to stay stable and grow slowly during the lifetime of the application. It is only the core state that is actually mutable and the actions always mutate only the core state. The derived state depends on the core state and is kept up-to-date by the MobX reactivity system. We know that computed properties act as the derived state in MobX. They can depend not only on the core state but also on other derived states, creating a dependency tree that is kept alive by MobX:

A key characteristic of the derived state is that it is read only...