Modules and applications

library(mstsap)
library(lobstr)
library(fs)

This vignette covers the standalone shiny apps in the mstsap package.

Apps from Mastering Shiny

Three of the applications in the mstsap package come from the Modules section of Mastering Shiny:

datasetApp()

• datasetApp() contains the datasetInput() and datasetServer() module functions

  • datasetInput() displays the objects from the datasets package ("dataset") matching filter argument (i.e., is.data.frame, is.matrix) and the table output ("data") in the UI

  • The inputId in the UI passes a datasets object (as input$dataset, a character string) to datasetServer(), which fetches and returns the object as a reactive via get()

█─datasetApp 
├─filter = NULL 
└─█─shinyApp 
  ├─ui = █─fluidPage 
  │      ├─█─datasetInput 
  │      │ ├─id = "dataset" 
  │      │ ├─filter = is.data.frame 
  │      │ └─█─selectInput 
  │      │   └─inputId = "dataset" 
  │      └─█─tableOutput 
  │        └─"data"
  └─server = █─function(input, output, session)
             └─█─data <- datasetServer(id = "dataset") 
               └─output$data <- renderTable(head(data()))

Reactive values

The output from reactiveValuesToList() are displayed in the dev version of this application:

$`dataset-dataset`
[1] "ability.cov"

The first dataset is from the module id, and the second is from the inputId (in the selectInput()).

selectVarApp()

• selectVarApp() contains the datasetInput()/Server() and selectVarInput()/Server() modules
  • dataset module:

    • datasetInput() displays the objects from the datasets package ("dataset") matching filter argument (i.e., is.data.frame, is.matrix) and the table output ("data") in the UI

    • The inputId in the UI passes a datasets object (as input$dataset, a character string) to datasetServer(), which fetches and returns the object as a reactive with get()

  • selectVar module:

    • selectVarInput() displays the variables (columns) in the returned datasets object from datasetServer() (as "var") and the rendered output (as "out")

    • In selectVarServer(), the columns in the data returned from datasetServer() is filtered to those columns matching the filter argument (i.e., is.numeric), and the selected "var" is displayed in "out"

█─selectVarApp 
└─█─shinyApp 
  ├─ui = █─fluidPage 
  │      ├─█─datasetInput 
  │      │ ├─id = "data" 
  │      │ ├─filter = is.data.frame
  │      │ └─█─selectInput 
  │      │   └─inputId = "dataset" 
  │      ├─█─selectVarInput 
  │      │ ├─id = "var" 
  │      │ └─█─selectInput 
  │      │   └─inputId = "var" 
  │      └─█─tableOutput 
  │        └─"out" 
  └─server = █─function(input, output, session)
             └─█─data <- datasetServer("data")
               █─var <- selectVarServer("var", data, filter = is.numeric)
               └─output$out <- renderTable(head(var()))
             

Reactive values

The output from reactiveValuesToList() for both modules are displayed in the dev version of the application:

$`var-var`
[1] "Ozone"

$`data-dataset`
[1] "airquality"

• The first "var" is from the selectVar module id, the second is from the selectInput()

• "data" is from the dataset module id, the second is from the selectInput()

selectDataVarApp()

• selectDataVarApp() nests the dataset and selectVar modules inside the selectDataVarUI() and selectDataVarServer() functions:
  • dataset module:

    • datasetInput() displays the objects from the datasets package ("dataset") matching filter argument (i.e., is.data.frame, is.matrix) and the table output ("data") in the UI

    • The inputId in the UI passes a datasets object (as input$dataset, a character string) to datasetServer(), which fetches and returns the object as a reactive with get()

  • selectVar module:

    • selectVarInput() displays the variables (columns) in the returned datasets object from datasetServer() (as "var") and the rendered output (as "out")

    • In selectVarServer(), the columns in the data returned from datasetServer() is filtered to those columns matching the filter argument (i.e., is.numeric), and the selected "var" is displayed in "out"

█─selectDataVarApp 
└─█─shinyApp 
  ├─ui = █─fluidPage 
  │      └─█─sidebarLayout 
  │        ├─█─sidebarPanel 
  │        │ └─█─selectDataVarUI 
  │        │   ├─"var" 
  │        │   ├─█─datasetInput 
  │        │   │ ├─█─NS 
  │        │   │ │ ├─id 
  │        │   │ │ └─"data" 
  │        │   │ └─filter = is.data.frame 
  │        │   └─█─selectVarInput 
  │        │     └─█─NS 
  │        │       ├─id 
  │        │       └─"var" 
  │        └─█─mainPanel 
  │          └─█─verbatimTextOutput 
  │            └─"out" 
  └─server = █─function(input, output, session)
             ├─█─var <- selectDataVarServer(id = "var", filter = is.numeric)
             │ ├─data <- datasetServer(id = "data")
             │ ├─var <- selectVarServer(id = "var", data, filter = filter) 
             │ └─var 
             └─output$out <- renderPrint(head(var()))