Update selectInput on the double click of table in Shiny App - r

Question

In the Shiny App below, I want to update the value of selectInput box based on the row that is double-clicked by the user in the table of tab 3. For example, if user double clicks at row 3 in the table, then the value of selectInput should change to 3.
Here is my code -
library(shiny)
library(shinydashboard)
siderbar <- dashboardSidebar(
sidebarMenu(
# Add buttons to choose the way you want to select your data
selectizeInput(inputId = "select_by", label = "Select by:",
choices = c(as.character(1:5)))
)
)
body <- dashboardBody(
fluidRow(
tabBox(
side = "right",
selected = "Tab3",
tabPanel("Tab1", "Tab content 1", textOutput("tabset1Selected")),
tabPanel("Tab2", "Tab content 2", textOutput("tabset2Selected")),
tabPanel("Tab3", "Tab content 3", textOutput("tabset3Selected"),
DT::dataTableOutput("table", width = "100%", height = "100%"), color="#bb0a1e", size = 1.5, type = 8)
)
),
)
shinyApp(
ui = dashboardPage(
dashboardHeader(title = "tabBoxes"),
siderbar,
body
),
server = function(session, input, output) {
# The currently selected tab from the first box
output$tabset1Selected <- output$tabset2Selected <- output$tabset3Selected <- renderText({
input$select_by
})
outputOptions(output, "tabset1Selected", suspendWhenHidden = FALSE)
outputOptions(output, "tabset2Selected", suspendWhenHidden = FALSE)
outputOptions(output, "tabset3Selected", suspendWhenHidden = FALSE)
table_dt <- reactive({data.table(values = c(1,2,3,4,5))})
output$table <- DT::renderDataTable({
DT::datatable(table_dt(), filter = 'top', selection = "single", fillContainer = TRUE, width = "90%",
callback = htmlwidgets::JS(
"table.on('dblclick', 'td',",
" function() {",
" var data = table.row(this).data();",
" Shiny.setInputValue('table_tbl_dblclick', {dt_data: data});",
" }",
");"
))
}
)
observeEvent(input$table_tbl_dblclick, {
reactTXT$selected <- input$table_tbl_dblclick$dt_data[[2]] # Since table index starts with 0, adding 1 to map index with data.table
})
reactTXT <- reactiveValues()
observeEvent(eventExpr = input$select_by, handlerExpr = {
req(input$select_by)
reactTXT$selected <- input$select_by
updateSelectizeInput(session, "select_by", selected = reactTXT$selected)
}, ignoreInit = TRUE)
}
)
Can someone point out the reason selectInput is not updated after clicking inside the table?

Answer 1

I don't quite understand what the purpose of your observeEvents are. If it is only to update the selectize input this one works for me:
observeEvent(input$table_tbl_dblclick, {
updateSelectizeInput(session, "select_by", selected = input$table_tbl_dblclick$dt_data[[2]])
})
Updated alternative to preserve reactTXT as the source of the new value:
observeEvent(input$table_tbl_dblclick, {
selected <- input$table_tbl_dblclick$dt_data[[2]] # Since table index starts with 0, adding 1 to map index with data.table
reactTXT$selected <- selected
})
reactTXT <- reactiveValues()
observeEvent(reactTXT$selected, handlerExpr = {
updateSelectizeInput(session, "select_by", selected = reactTXT$selected)
}, ignoreInit = TRUE)
From comments below