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

Keeping our API alive with PM2

We are running our Node.js process inside an ephemeral SSH session. When we log out, the host machine will kill any processes initiated during that session. Therefore, we need to come up with a way of keeping our process alive even after logging out.

Furthermore, no matter how good our code base is, or how complete our test plans are, in any application of significant size, there will be errors. Sometimes, these errors are fatal and crash the application. In these instances, we should log the error and notify the developers, but most importantly, we should restart the application as soon as it crashes.

Ubuntu provides the upstart daemon (, which can monitor a service and respawn it if it dies unexpectedly. Likewise, there's a popular npm package called forever (, which does a similar job. However, I have found PM2 ( to be the best process manager out there, so that's what we'll use in this book...