The Factory Method pattern, sometimes referred to as the Virtual Constructor pattern, provides a way to conceal an object's creation logic from client code, but the object returned is guaranteed to adhere to a known interface. It's one of the most widely used creational

In cases where you have a large number of subsystems, each with its own simple or complicated interface, it can sometimes be to your advantage to abstract away those interfaces by unifying them under one common, usually simpler interface. This is the essence of

The Flyweight pattern is all about using memory efficiently. If your Dart or Flutter app deals with relatively heavy objects, and it needs to instantiate many of them, using this pattern can help save memory and increase performance by avoiding data duplication. Objects that

With the Adapter pattern, you create an intermediary between two incompatible class interfaces, allowing one to work with the other. This works very much like physical adapters in the real world, such as those that attach to a power cord to enable a device

The general structure of the Composite pattern will be instantly familiar to Flutter developers, because Flutter's widgets are constructed with an expanded version. Regular Flutter widgets, defined as those that can have only one child, and collection Flutter widgets, defined as those that take

Using inheritance, we can statically extend the functionality of a Dart class. But what if we want more flexibility than that? We may want to add behavior to an object dynamically, perhaps as a user makes attribute selections. The Decorator pattern can help! With

When you need to ensure only a single instance of a class is created, and you want to provide a global point of access to it, the Singleton design pattern can be of great help. Examples of typical singletons include an app-wide debug logger

The purpose of the Builder pattern is to separate the construction of a complex object from its representation. This is especially useful for objects with many properties, some of which may have obvious defaults, and some of which may be optional. Early object-oriented languages

Sometimes you need to create a copy, or clone, of an existing object. For mutable objects with properties that can change, you may need a separate copy of an object to avoid corrupting the original. For immutable objects, where properties can be initialized but

Streams and sinks are mainstays in Dart and Flutter asynchronous programming, and now it's time to explore what streams are and how they can be used to solve problems. The code for this article was tested with Dart 2.8.4 and Flutter 1.

Even though Dart, with its convenient async/await syntax, is able to take a lot of the complexity out of managing asynchronous calls, sometimes you need to interact with a more traditional callback library or a persistent connection that doesn't operate with futures. In

The UI widgets available in the Flutter framework use Dart's asynchronous programming features to great effect, helping to keep your code organized and preventing the UI from locking up on the user. In this article, we'll look at how asynchronous code patterns can help

Dart is a single-threaded language. This trait is often misunderstood. Many programmers believe this means Dart can't run code in parallel, but that's not the case. So how does Dart manage and execute operations? The code for this article was tested with Dart 2.

Immutable data constructs are those that cannot be mutated (altered) after they've been initialized. The Dart language is full of these. In fact, most basic variable types operate this way. Once created, strings, numbers, and boolean values cannot be mutated. A string variable doesn't