In the previous chapter, we looked at R, learned some of its basic syntax, and saw some examples of the power and flexibility that R and Shiny offer. This chapter introduces the basics of Shiny. In this chapter, we're going to build our own application to interactively explore the Gapminder data described in the previous chapter. We will cover the following topics:

• The types of Shiny application—R Markdown, single-file, two-file, Shiny gadgets
• Interactive Shiny documents in R Markdown
• Single-file Shiny applications
• Two-file Shiny applications
• A minimal example of a full Shiny application
• Widget types
• The basic structure of a Shiny program
• The selection of simple input widgets (checkboxes and combo buttons)
• The selection of simple output types (rendering plots and maps, and returning text)
• The selection of simple layout types (page with sidebar and tabbed output panel)
• Reactive objects
• A brief summary of more advanced layout features