Shiny R: Interactive toggle output with `input` data selection - r

Question

I have a question about the data selection of interactive toggle shiny app. I would like to make the data selected from selectInput but the error say: Operation not allowed without an active reactive context. (You tried to do something that can only be done from inside a reactive expression or observer.)
Is there any way to make the data interactive with the input?
Thank you!
Here is my app:
app.r:
ui <- fluidPage(
fluidRow(
column(width = 6,
selectInput("vsselection", "Choose a vs:",
choices = names(table(data.frame(mtcars$vs))),selected=0),
plotOutput("plot1", height = 350,
click = "plot1_click",
brush = brushOpts(
id = "plot1_brush"
)
),
actionButton("exclude_toggle", "Toggle points"),
actionButton("exclude_reset", "Reset")
)
)
)
server <- function(input, output) {
# For storing which rows have been excluded
vals <- reactiveValues(
keeprows = rep(TRUE, nrow(mtcars[which(mtcars$vs==input$vsselection),]))
)
output$plot1 <- renderPlot({
# Plot the kept and excluded points as two separate data sets
keep <- mtcars[which(mtcars$vs==input$vsselection),][ vals$keeprows, , drop = FALSE]
exclude <- mtcars[which(mtcars$vs==input$vsselection),][!vals$keeprows, , drop = FALSE]
ggplot(keep, aes(wt, mpg)) + geom_point() +
geom_smooth(method = lm, fullrange = TRUE, color = "black") +
geom_point(data = exclude, shape = 21, fill = NA, color = "black", alpha = 0.25) +
coord_cartesian(xlim = c(1.5, 5.5), ylim = c(5,35))
})
# Toggle points that are clicked
observeEvent(input$plot1_click, {
res <- nearPoints(mtcars[which(mtcars$vs==input$vsselection),], input$plot1_click, allRows = TRUE)
vals$keeprows <- xor(vals$keeprows, res$selected_)
})
# Toggle points that are brushed, when button is clicked
observeEvent(input$exclude_toggle, {
res <- brushedPoints(mtcars[which(mtcars$vs==input$vsselection),], input$plot1_brush, allRows = TRUE)
vals$keeprows <- xor(vals$keeprows, res$selected_)
})
# Reset all points
observeEvent(input$exclude_reset, {
vals$keeprows <- rep(TRUE, nrow(mtcars[which(mtcars$vs==input$vsselection),]))
})
}
shinyApp(ui, server)

Answer 1

I guess the first thing you should to, is to change vals to vals <- reactive({...}) and then when referring to it, add parenthesis, e.g. vals()$keeprows. This should solve the reactivity problem.

Answer 2

Finally, I solved this issue by removing the interactive part from the object of reactiveValues() by keep the interactive part of Vals.
Note that values taken from the reactiveValues object are reactive, but the reactiveValues object itself is not.
Here is my app:
app.r:
ui <- fluidPage(
fluidRow(
column(width = 6,
selectInput("vsselection", "Choose a vs:",
choices = names(table(data.frame(mtcars$vs))),selected=0),
plotOutput("plot1", height = 350,
click = "plot1_click",
brush = brushOpts(
id = "plot1_brush"
)
),
actionButton("exclude_toggle", "Toggle points"),
actionButton("exclude_reset", "Reset")
)
)
)
server <- function(input, output) {
# For storing which rows have been excluded
vals <- reactiveValues(
keeprows = rep(TRUE, nrow(mtcars))
)
output$plot1 <- renderPlot({
# Plot the kept and excluded points as two separate data sets
keep <- mtcars[which(mtcars$vs==input$vsselection),][ vals$keeprows, , drop = FALSE]
exclude <- mtcars[which(mtcars$vs==input$vsselection),][!vals$keeprows, , drop = FALSE]
ggplot(keep, aes(wt, mpg)) + geom_point(color = "blue") +
geom_smooth(method = lm, fullrange = TRUE, color = "black") +
geom_point(data = exclude, shape = 21, fill = NA, color = "black", alpha = 0.25)
})
# Toggle points that are clicked
observeEvent(input$plot1_click, {
res <- nearPoints(mtcars[which(mtcars$vs==input$vsselection),], input$plot1_click, allRows = TRUE)
vals$keeprows <- xor(vals$keeprows, res$selected_)
})
# Toggle points that are brushed, when button is clicked
observeEvent(input$exclude_toggle, {
res <- brushedPoints(mtcars[which(mtcars$vs==input$vsselection),], input$plot1_brush, allRows = TRUE)
vals$keeprows <- xor(vals$keeprows, res$selected_)
})
# Reset all points
observeEvent(input$exclude_reset, {
vals$keeprows <- rep(TRUE, nrow(mtcars[which(mtcars$vs==input$vsselection),]))
})
}