Problem with Shiny and Plotly. Error in UseMethod - r

Question

I am trying to render plotly based on the input selection. I am receiving an error: Warning: Error in UseMethod: no applicable method for 'layout' applied to an object of class "shiny.tag".
library(dplyr)
library(ggplot2)
library(shiny)
library(shinydashboard)
library(ggplot2)
library(plotly)
library(plotDK)
df <- tibble(postnr = c(4000, 2000,9000),
kommunekoder = c(101, 147,153),
reg_code = c(1,2,3),
count = c(3,5,6))
ui <- shinyUI(fluidPage(
box(plotlyOutput("map")),
box(selectInput(
"level",
label= "Select map level:",
choices = c("Zip code", "Municipality", "Region"),
multiple = FALSE,
selected = "Zip code"),
solidHeader = TRUE,
width = "5",
height = "75px",
status = "primary"
)))
server <- shinyServer(function(input, output) {
plot <- reactive({ifelse(input$level == "Zip code", plotDK(plotlevel = "zipcode", value = "count", id ="postnr" , data = df, show_missing = TRUE),
ifelse(input$level == "Municipality", plotDK(plotlevel = "municipality", value = "count", id ="kommunekoder" , data = df, show_missing = TRUE),
plotDK(plotlevel = "region", value = "count", id ="reg_code" , data = df, show_missing = TRUE)))})
output$map <- renderPlotly({ggplotly(plot() + scale_fill_continuous(name ="Number of firms")) %>% layout(height = 500, width = 650)
})
})
shinyApp(ui = ui, server)
If I run the code in outside Shiny, it works:
plot <- plotDK(plotlevel = "region", value = "count", id ="reg_code" , data = df, show_missing = TRUE)
ggplotly(plot + scale_fill_continuous(name ="Number of firms")) %>% layout(height = 500, width = 650)
What am I missing?

Answer 1

Would it be possible to change your Server function to:
server <- shinyServer(function(input, output) {
output$map <- renderPlotly({
if(input$level == "Zip code"){
p <- plotDK(plotlevel = "zipcode", value = "count", id ="postnr" ,
data = df, show_missing = TRUE)
}
if(input$level == "Municipality"){
p <- plotDK(plotlevel = "municipality", value = "count", id ="kommunekoder" ,
data = df, show_missing = TRUE)
}
if(input$level == "Region"){
p <- plotDK(plotlevel = "region", value = "count", id ="reg_code" ,
data = df, show_missing = TRUE)
}
ggplotly(p + scale_fill_continuous(name ="Number of firms")) %>% layout(height = 500, width = 650)
})
})
This embeds the plotting function inside the map output. If you really need the plot to be stored in a reactive, then this won't work, but if you just need to make the plot so it can be rendered in the output, this should do the trick.