Dart Streams

Introduction to Dart Streams

Dart Streams provide a way to handle a sequence of asynchronous data. Streams are essential when working with data that is produced over time, such as file I/O, network requests, or user inputs. Streams can be single-subscription or broadcast, and they are managed through StreamController objects, which allow you to control and listen to the stream of data efficiently.

Creating a Stream with StreamController

A StreamController allows you to create a stream and add data to it. Let's see how you can create a simple stream using StreamController and listen to the data:

Understanding Single-Subscription vs Broadcast Streams

Streams in Dart can either be single-subscription or broadcast. A single-subscription stream allows only one listener, while a broadcast stream can have multiple listeners. By default, StreamController creates a single-subscription stream. To create a broadcast stream, you can use StreamController.broadcast().

Handling Errors in Streams

When dealing with streams, error handling is crucial. You can handle errors in a stream by providing an onError callback in the listen method. Here's an example:

Transforming Stream Data

Dart streams can be transformed using methods like map, where, and expand. These methods allow you to manipulate the data as it passes through the stream. Here's an example of transforming stream data:

Conclusion

Dart Streams are a powerful feature for handling asynchronous data. They provide a flexible way to work with events and data sequences, and are extremely useful for tasks like network requests, user input, and more. By mastering streams, you can significantly enhance the responsiveness and efficiency of your Dart applications.