Difference between flutter_bloc Library and RxDart

Learn about the differences between flutter_bloc and RxDart state management solutions.

This lesson will explain the difference between the flutter_bloc library and RxDart and discuss how RxDart works.

The flutter_bloc library and RxDart are both popular state management solutions. Both of these solutions help us implement the BLoC pattern in their own ways.

What is RxDart?

RxDart is a library that provides reactive programming extensions to Dart. It’s based on the ReactiveX API, which is a popular API for reactive programming.

Reactive programming is a programming paradigm that enables developers to write asynchronous, event-driven code. This is the paradigm that Dart’s Streams API originally helped us obtain. If you want a refresher on what streams are, you can go back to the Streams lesson of this course.

What RxDart does is add to Dart’s original Streams API. It gives it superpowers that help us gain more stream classes, operators, and subjects.

Differences between flutter_bloc library and RxDart

BLoC and RxDart are both powerful state management solutions, but they have some key differences.


The flutter_bloc library is designed specifically for Flutter development and provides a way to separate the business logic from the UI. It it’s a more focused solution that provides a clear separation of concerns.

RxDart, on the other hand, is a more general-purpose library that can be used in any Dart project. It doesn’t necessarily have to be used to implement the BLoC pattern. It provides a way to handle complex data flows and streamline development.

Ease of use

The flutter_bloc library and RxDart are challenging to learn, especially for people new to reactive programming. When it comes to implementing the BLoC pattern, RxDart has a steeper learning curve than flutter_bloc. This is because RxDart requires us to implement the BLoC library manually using streams, while flutter_bloc gives us widgets and functions that help us easily create the BLoC pattern.

Advantages of RxDart

  • RxDart’s observables can push data, errors, and completion signals, whereas Dart Streams only emit data events and can throw errors but don’t have a built-in completion signal. A completion signal is a notification that a stream has completed its work and will not emit any more events. This signal is useful for determining when to clean up resources associated with the stream or when to perform additional processing after the stream has finished.

  • RxDart was designed for asynchronous programming with an emphasis on concurrency and parallelism, while Dart Streams can be used for both synchronous and asynchronous programming but don’t have the same emphasis on concurrency and parallelism.

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