MobX vs RxJS: What are the differences?

Introduction

MobX and RxJS are both popular libraries used in JavaScript for managing the state of an application. While they have some similarities, there are key differences between the two in terms of their core principles and functionalities. In this Markdown code, we will discuss six main differences between MobX and RxJS.

1. Reactive Data Flow: MobX provides reactive data flow where changes in the state are observed and automatically propagated to the dependent parts of the application. On the other hand, RxJS is based on streams and provides a declarative way of handling asynchronous data streams, allowing for powerful data manipulation and composition.

2. Imperative vs Declarative Programming: MobX follows an imperative programming style, where developers define how the state should change based on observed events. Conversely, RxJS follows a declarative programming style, allowing developers to define the desired end state and letting the library handle how to achieve it, abstracting away the underlying implementation details.

3. Mutable State vs Immutable State: MobX operates on mutable state, where objects and arrays can be changed directly. It uses observable objects to track changes and automatically update the application. In contrast, RxJS prefers immutable state, focusing on the creation of new data streams through transformations and filters, making it easier to reason about the state.

4. React Integration: MobX has seamless integration with React, making it easy to manage and update the state of React components. It provides a simple approach to define reactive components, where only necessary parts of the UI are updated when relevant data changes. On the other hand, RxJS can also be integrated with React but requires more manual handling and setup to enable reactive behavior.

5. Granularity of Control: MobX provides fine-grained control over which parts of the application should be observed for changes. This allows developers to optimize performance by only updating relevant components. RxJS, on the other hand, provides more coarse-grained control as changes in the data streams can potentially affect multiple parts of the application.

6. Learning Curve: MobX has a relatively shallow learning curve, especially for developers already familiar with object-oriented programming and React. It provides a simple and intuitive API to manage state. In contrast, RxJS has a steeper learning curve due to its functional approach and the need to understand concepts such as observables, operators, and subscriptions.

In summary, while both MobX and RxJS provide solutions for managing state in JavaScript applications, MobX offers reactive data flow, follows an imperative programming style, operates on mutable state, has seamless React integration, provides fine-grained control, and has a relatively shallow learning curve. In contrast, RxJS focuses on streams, follows a declarative programming style, prefers immutable state, requires additional setup for React integration, provides more coarse-grained control, and has a steeper learning curve.