Book Image

Node.js Design Patterns - Third Edition

By : Mario Casciaro, Luciano Mammino
5 (1)
Book Image

Node.js Design Patterns - Third Edition

5 (1)
By: Mario Casciaro, Luciano Mammino

Overview of this book

In this book, we will show you how to implement a series of best practices and design patterns to help you create efficient and robust Node.js applications with ease. We kick off by exploring the basics of Node.js, analyzing its asynchronous event driven architecture and its fundamental design patterns. We then show you how to build asynchronous control flow patterns with callbacks, promises and async/await. Next, we dive into Node.js streams, unveiling their power and showing you how to use them at their full capacity. Following streams is an analysis of different creational, structural, and behavioral design patterns that take full advantage of JavaScript and Node.js. Lastly, the book dives into more advanced concepts such as Universal JavaScript, scalability and messaging patterns to help you build enterprise-grade distributed applications. Throughout the book, you’ll see Node.js in action with the help of several real-life examples leveraging technologies such as LevelDB, Redis, RabbitMQ, ZeroMQ, and many others. They will be used to demonstrate a pattern or technique, but they will also give you a great introduction to the Node.js ecosystem and its set of solutions.
Table of Contents (16 chapters)
14
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15
Index

Command

Another design pattern with huge importance in Node.js is Command. In its most generic definition, we can consider a command any object that encapsulates all the information necessary to perform an action at a later time. So, instead of invoking a method or a function directly, we create an object representing the intention to perform such an invocation. It will then be the responsibility of another component to materialize the intent, transforming it into an actual action. Traditionally, this pattern is built around four major components, as shown in Figure 9.6:

Figure 9.6: The components of the Command pattern

The typical configuration of the Command pattern can be described as follows:

  • Command is the object encapsulating the information necessary to invoke a method or function.
  • Client is the component that creates the command and provides it to the invoker.
  • Invoker is the component responsible for executing the command...