showLog: Print any JavaScript console.log messages in the R console

Description Usage Note See Also Examples

View source: R/showLog.R

Description

When developing and debugging a Shiny that uses custom JavaScript code, it can be helpful to use console.log() messages in JavaScript. This function allows you to see these messages printed in the R console directly rather than having to open the JavaScript console in the browser to view the messages.

This function must be called in a Shiny app's server.

Usage

1

Note

Log messages that cannot be serialized in JavaScript (such as many JavaScript Event objects that are cyclic) will not be printed in R.

See Also

logjs

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
if (interactive()) {
  library(shiny)

  shinyApp(
    ui = fluidPage(
      useShinyjs(),
      textInput("text", "Type something")
    ),
    server = function(input, output) {
      showLog()
      logjs("App started")
      observe({
        logjs(paste("Length of text:", nchar(input$text)))
      })
    }
  )
}

Example output

Attaching package: 'shinyjs'

The following objects are masked from 'package:methods':

    removeClass, show

shinyjs documentation built on Sept. 13, 2020, 5:14 p.m.