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

High reliability

Reliability is a measure of the confidence in a system, and is inversely proportional to the probability of failure.

Reliability is measured using several metrics:

  • Mean time between failures (MTBF): Uptime/number of failures
  • Mean time to repair (MTTR): The average time it takes the team to fix a failure and return the system online

Testing for reliability

The easiest way to increase reliability is to increase test coverage of the system. This is, of course, assuming that those tests are meaningful tests.

Tests increase reliability by:

  • Increasing MTBF: The more thorough your tests, the more likely you'll catch bugs before the system is deployed.
  • Reducing MTTR: This is because historical test results inform you of the last version which passes all tests. If the application is experiencing a high level of failures, then the team can quickly roll back to the last-known-good version.