Book Image

Web Application Development with R Using Shiny - Third Edition

By : Chris Beeley, Shitalkumar R. Sukhdeve
Book Image

Web Application Development with R Using Shiny - Third Edition

By: Chris Beeley, Shitalkumar R. Sukhdeve

Overview of this book

Web Application Development with R Using Shiny helps you become familiar with the complete R Shiny package. The book starts with a quick overview of R and its fundamentals, followed by an exploration of the fundamentals of Shiny and some of the things that it can help you do. You’ll learn about the wide range of widgets and functions within Shiny and how they fit together to make an attractive and easy to use application. Once you have understood the basics, you'll move on to studying more advanced UI features, including how to style apps in detail using the Bootstrap framework or and Shiny's inbuilt layout functions. You'll learn about enhancing Shiny with JavaScript, ranging from adding simple interactivity with JavaScript right through to using JavaScript to enhance the reactivity between your app and the UI. You'll learn more advanced Shiny features of Shiny, such as uploading and downloading data and reports, as well as how to interact with tables and link reactive outputs. Lastly, you'll learn how to deploy Shiny applications over the internet, as well as and how to handle storage and data persistence within Shiny applications, including the use of relational databases. By the end of this book, you'll be ready to create responsive, interactive web applications using the complete R (v 3.4) Shiny (1.1.0) suite.
Table of Contents (11 chapters)

Shinytest

Let's say that the Shiny application we have developed runs well on our machine for some input, but for others it does not give the desired output or it gets stuck somewhere and throws errors. In the software development process, testing is one of the most important tasks. A Shiny application might stop working due to any of the following reasons:

  • The version of Shiny and the version of the packages may differ
  • A modification in the application code leads to the wrong input for any other reactive code
  • The data format may have changed

There may be countless reasons that cause us to come across errors and cause the application to stop working. Doing testing manually can be time-consuming and inefficient because you have to consider a wide range of use cases. For this reason, Shiny has the shinytest package for automatic testing. It can be installed as follows (https...