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

Async/await

As we have just seen, promises are a quantum leap ahead of callbacks. They allow us to write clean and readable asynchronous code and provide a set of safeguards that can only be achieved with boilerplate code when working with callback-based asynchronous code. However, promises are still suboptimal when it comes to writing sequential asynchronous code. The Promise chain is indeed much better than having callback hell, but still, we have to invoke a then() and create a new function for each task in the chain. This is still too much for a control flow that is definitely the most commonly used in everyday programming. JavaScript needed a proper way to deal with the ubiquitous asynchronous sequential execution flow, and the answer arrived with the introduction in the ECMAScript standard of async functions and the await expression (async/await for short).

The async/await dichotomy allows us to write functions that appear to block at each asynchronous operation, waiting...