Shiny app containing rintrojs code won't run in VSCode

[David-Kingman]

I have a shiny app which I originally developed using RStudio which I have been trying to run locally in VSCode (in both cases on a Windows 10 virtual machine). However, this doesn't work because of an error which only occurs when I try and run the app in VSCode, and not when I run exactly the same code in RStudio with the same version of R and the same package versions.

It appears to be being caused by the inclusion of code from the rintrojs library which includes some characters which VSCode thinks are invalid UTF-8 characters, triggering an error, but which RStudio does not have a problem with.

This is the error message I get in VSCode:

I have managed to create a minimally reproducible example of the problem I get in my app (I have highlighted the line which is causing the error):

library(shiny)
library(rintrojs)

# Define UI for application that draws a histogram
ui <- fluidPage(
  
  # Commenting the line below out stops the error from happening in VSCode, whereas including it is what triggers the error!
  rintrojs::introjsUI(),

    # Application title
    titlePanel("Old Faithful Geyser Data"),

    # Sidebar with a slider input for number of bins 
    sidebarLayout(
        sidebarPanel(
            sliderInput("bins",
                        "Number of bins:",
                        min = 1,
                        max = 50,
                        value = 30)
        ),

        # Show a plot of the generated distribution
        mainPanel(
           plotOutput("distPlot")
        )
    )
)

# Define server logic required to draw a histogram
server <- function(input, output) {

    output$distPlot <- renderPlot({
        # generate bins based on input$bins from ui.R
        x    <- faithful[, 2]
        bins <- seq(min(x), max(x), length.out = input$bins + 1)

        # draw the histogram with the specified number of bins
        hist(x, breaks = bins, col = 'darkgray', border = 'white',
             xlab = 'Waiting time to next eruption (in mins)',
             main = 'Histogram of waiting times')
    })
}

# Run the application 
shinyApp(ui = ui, server = server)

I can run this code in RStudio with the line I have highlighted either included or not included and the app will load. However, if I leave that line in the code and try and run it in VSCode, then it will produce the error message I have shared above.

I have identified the characters which trigger the error message and they actually originate in the javascript package which that R function is providing a wrapper around, so I am not sure to what extent this is a R issue.

Environment (please complete the following information):

• OS: Windows 10
• VSCode Version: 1.90.1
• R Version: 4.4.1
• vscode-R version: 2.8.4
• rintrojs Version: 0.3.2
• shiny Version: 1.9.1