Dart in Action

Chapter 9. Asynchronous programming with callbacks and futures

This chapter covers

• The nonblocking async programming model
• Callbacks for asynchronous APIs
• Improving asynchronous readability with futures and completers
• Unit-testing asynchronous code

In web programming, you can’t rely on events outside your application’s control happening in a specific order. In the browser, retrieving data from a server might take longer than you expect, and instead of waiting for the data, a user might click another button. A Dart server application will likely need to handle a new request for data before a previous request has finished reading data from the file system. This type of programming is known as an asynchronous model (async), and its counterpart ...