Reactivity helper

The react object gives alternative syntax to call shiny reactive expressions.

Usage

react(x)

Arguments

x

the reactive call

Details

The benefit is that it makes them easier to spot in your code.

Examples

# This works by invoking the function from the parent environment
# with no arguments ...
foo <- function() {
  42
}
react$foo
#> [1] 42
react[foo]
#> Error in get(as.character(expr, frame)): object 'foo' not found
react[foo()]
#> Error in get(as.character(expr[[1L]], frame)): object 'foo' not found

# You can also use `react()` as a function to wrap the
# reactive call
react(foo())
#> [1] 42

# The benefit is that `react()` can also wrap `input$` calls
# so that you easily recognize reactivity

if (FALSE) {
  # ... but it only becomes relevant when used in shiny
  # server code, e.g. this app from the shiny page
  # with react$dataInput instead of dataInput()
  server <- function(input, output) {

    dataInput <- reactive({
      getSymbols(input$symb, src = "yahoo",
          from = input$dates[1],
            to = input$dates[2],
            auto.assign = FALSE)
    })

    output$plot <- renderPlot({
       chartSeries(react$dataInput, theme = chartTheme("white"),
              type = "line", log.scale = input$log, TA = NULL)
    })
  }
}