We have briefly introduced Shiny documents in Section 2.8.2. Shiny is a very powerful framework for building web applications based on R. It is out of the scope of this book to make a comprehensive introduction to Shiny (which is too big a topic). We recommend that readers who are not familiar with Shiny learn more about it from the website https://shiny.rstudio.com before reading this chapter.
Unlike the more traditional workflow of creating static reports, you can create documents that allow your readers to change the parameters underlying your analysis and see the results immediately in Shiny R Markdown documents. In the example shown in Figure 2.8, the histogram will be automatically updated to reflect the number of bins selected by the reader.
A picture is worth a thousand words, and a Shiny document can potentially show you a thousand pictures as you interact with it. The readers are no longer tied to the fixed analysis and conclusions in the report. They may explore other possibilities by themselves, and possibly make new discoveries or draw different conclusions.