c3 charts behave inconsistently in shiny

[SNaveenMathew]

Disclaimer: I'm unable to produce 'reproducible' code because of the following reasons:

• In one R shiny app c3_pie works but c3_gauge does not
• In another R shiny app c3_gauge works but c3_pie does not
• In another R shiny app neither of these work

Definition: "not working": svg is created and rendered in the browser, but it is blank

The input types for charts are:

• c3_pie: data frame with 1 row and several columns
• c3_gauge: data frame with 1 row and 1 column

Summary of attempts, successes and failures:

The input to charts is a reactiveValues object that updates based on user's inputs. In both cases I'm using c3::c3Output(...) and defined a suitable output$... <- c3::renderC3({ ... }). To be safe I avoided using %>% and returned c3_pie() or c3_gauge object. I saved (cached) the data frame used for plotting, read it in R and plotted (c3_gauge or c3_pie) - it worked as expected. I also observed that replacing the dynamic data with static data (Eg: data.frame(x=10, y=10)) makes the plot appear in R shiny. I experimented a bit more and found that there is no clear relationship between the type of data (reactive or static) and the behavior of the R shiny output.

Is there a universal fix for this problem?

[mrjoh3]

Hi @SNaveenMathew, it sound like it is an issue with your reactive element. Please produce a minimal version based on the code below. This works fine add your reactive code until it does not work then I can attempt to debug:

library(shiny)
library(c3)

ui <- fluidPage(
        c3Output("plot")
)

server <- function(input, output) {

   output$plot <- renderC3({
     data.frame(x=10, y=10) %>%
       c3() %>%
       #c3_pie()
       c3_gauge()
   })
}

shinyApp(ui = ui, server = server)

[SNaveenMathew]

My apologies, I'm not able to produce a minimal reproducible example. I went with the temporary fix - I changed the type of chart from

• pie to gauge if pie chart did not work
• gauge to pie if gauge chart did not work
• other plotting systems (ggplot2) if both did not work

I will reopen this issue if I find a more concrete explanation.