Warnings : JsonLite in shiny app

Hi,
Using ggplot function in a shiny output, i receive this warning only when x-axis is reduced to single factor.

" Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON. "

If x-axis is > 1 factor, works without warning.

I tried to convert my dataset(dataframe) in a named list :

df <- data.frame(table(type)) 
colnames(df) <- c("Var1", "Var2")
df$Var1 <- fct_rev(df$Var1)

dataset <- list(df)
names(dataset) <- "Test"

Then use the ggplot function but nothing changes :

graph <- ggplot(dataset$Test, aes(x=Var1, y=Var2))
graph_dyn <- graph + coord_flip()
graph_dyn

If not possible, is there a way to not display the Json warning in the console?

options(warn=-1) # not working

I don't know what's going on that it would mention jsonLite anywhere in relation to what you are doing...
What happens when you run this reprex ?

library(ggplot2)
Var1 <- as.factor(c(1,1,1))
Var2 <- c(1,2,3)

dataset <- data.frame(
  Var1,
  Var2
)
graph <- ggplot(dataset, aes(x=Var1, y=Var2))
graph_dyn <- graph + coord_flip()


graph_dyn+geom_point()

mydflist <- list(dataset)
names(mydflist) <- "Test"

graph <- ggplot(mydflist$Test, aes(x=Var1, y=Var2))
graph_dyn <- graph + coord_flip()


graph_dyn+geom_point()

oh, and in general you might use suppressWarnings() function

Hi,

I found the same problem (better explained) on this topic : https://github.com/rstudio/shiny/issues/2673

Running the following example, as you can see, the second part generates Json message :

library(shiny)
library(ggplot2)

ui <- fluidPage(
            tabsetPanel(
                tabPanel("no message", plotOutput("quietPlot")),
                tabPanel("generates `Input to asJSON` message", plotOutput("noisyPlot"))
            )
)

# Define server logic required to draw cols
server <- function(input, output, session) {
    output$quietPlot <- renderPlot({
        ggplot(
            data = data.frame(z = c("a", "b"), n = c(1, 2)),
            aes(x = z, y = n)
        ) + geom_col()
    })
    output$noisyPlot <- renderPlot({
        ggplot(
            data = data.frame(z = c("a"), n = c(1)),
            aes(x = z, y = n)
        ) + geom_col() 
    })
}

shinyApp(ui = ui, server = server)

In my case, dataset come from a reactive function, so x-axis can have 1 or multiple factors : the Json message appears in the R console when only 1 factor in the variable.

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weird bug ! I did experience it in your reprex.
I found a way to make it go away.
relies on loading plotly library, changing from plotOutput to plotlyOutput, and finally from renderPlot to renderPlotly. Everything else the same the warning disappears.

library(plotly)
plotlyOutput("noisyPlot")
renderPlotly({

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