Book Image

Building Enterprise JavaScript Applications

By : Daniel Li
Book Image

Building Enterprise JavaScript Applications

By: Daniel Li

Overview of this book

With the over-abundance of tools in the JavaScript ecosystem, it's easy to feel lost. Build tools, package managers, loaders, bundlers, linters, compilers, transpilers, typecheckers - how do you make sense of it all? In this book, we will build a simple API and React application from scratch. We begin by setting up our development environment using Git, yarn, Babel, and ESLint. Then, we will use Express, Elasticsearch and JSON Web Tokens (JWTs) to build a stateless API service. For the front-end, we will use React, Redux, and Webpack. A central theme in the book is maintaining code quality. As such, we will enforce a Test-Driven Development (TDD) process using Selenium, Cucumber, Mocha, Sinon, and Istanbul. As we progress through the book, the focus will shift towards automation and infrastructure. You will learn to work with Continuous Integration (CI) servers like Jenkins, deploying services inside Docker containers, and run them on Kubernetes. By following this book, you would gain the skills needed to build robust, production-ready applications.
Table of Contents (26 chapters)
Title Page
Copyright and Credits
Packt Upsell
Free Chapter
The Importance of Good Code

Modularizing React

But for now, we must solve another pressing issue - our code is not very modular. Everything is defined inside a single <script> tag. Not only is this hard to read, but it is also not maintainable. We can't define every component in one file!

Furthermore, we are including libraries using <script> tags. Because some libraries depend on others (for example, react-dom depends on react), we must manually ensure our scripts are loaded in the right order.

We have already looked at CommonJS and ES6 modules when we discussed server-side modules. However, we must consider other factors when using modules on client-side code, such as:

  • The size of each module. Dependencies are downloaded before the application is run. On the server, the application is only initialized once, after which it will keep running for a long time (weeks to years). Therefore, the initial time required for downloading dependencies is a one-time cost. On the client, however, these dependencies need...