Observe multiple shiny inputs in a div with an id - r

Question

Problem Statement:
Say I have multiple inputs in a wellPanel which has id = "my_inputs". Below the wellPanel is a button labelled "Calculate".
The button is only enabled if all user inputs are valid ie. Not blanks and Not NULL.
To do that I've had to check the validity of each of them, one by one using:
valid_inputs <- reactive({
inputs <- c(input$input1, input$input2, input$input3)
purrr::map_lgl(.x = inputs, .f = is_valid) |> all()
})
That works fine. The problem is that I have 3 tabs each with 10 inputs and typing out c(input$input1, input$input2, input$input3, ..., input$input10) is kind of tiring considering the inputId's are different and NOT sequential. Also, each tab has its own different inputs so they are not similar.
Question:
Is there a way to check for the inputs' validity using the id of the wellPanel?
Something along the lines of:
is_valid(id = "my_inputs")
Reprex:
library(shiny)
library(shinyjs)
ui <- fluidPage(
shinyjs::useShinyjs(),
wellPanel(
id = "my_inputs",
fluidRow(
column(
width = 4,
selectInput(
inputId = "input1",
label = "Input 1",
choices = letters[1:3]
)
),
column(
width = 4,
textInput(
inputId = "input2",
label = "Input 2",
placeholder = "Enter name"
)
),
column(
width = 4,
selectInput(
inputId = "input3",
label = "Input 3",
choices = c("", letters[4:6])
)
)
)
),
fluidRow(
column(
width = 12,
align = "center",
actionButton(
inputId = "actionbtn",
label = "Calculate",
class = "btn-success"
)
)
)
)
server <- function(input, output, session) {
# fn to check if an input is valid:
is_valid <- function(x) {
x != "" && !is.null(x) # input should NOT be blank or NULL
}
# Map that function over all inputs:
valid_inputs <- reactive({
inputs <- c(input$input1, input$input2, input$input3)
purrr::map_lgl(.x = inputs, .f = is_valid) |> all()
})
# if all inputs are valid, enable calculate btn, else disable:
observe(
shinyjs::toggleState(
id = "actionbtn",
condition = valid_inputs()
)
)
}
shinyApp(ui, server)

Answer 1

In that case you can grab the input ids with reactiveValuesToList, and apply your validation function to each element.
server <- function(input, output, session) {
# Capture all input ids
ui_inputs <- reactive({
x <- names(reactiveValuesToList(input))
x[startsWith(x, "input")] # ignore actionbtn
})
# fn to check if an input is valid:
is_valid <- function(x) {
x != "" && !is.null(x) # input should NOT be blank or NULL
}
# Check if all input ids are valid using your function
valid_inputs <- reactive({
x <- lapply(ui_inputs(), function(x) is_valid(input[[x]]) )
all(x)
})
# if all inputs are valid, enable calculate btn, else disable:
observe(
shinyjs::toggleState(
id = "actionbtn",
condition = valid_inputs()
)
)
}
shinyApp(ui, server)

Answer 2

Here is an alternative approach using tagQuery from library(htmltools) to extract the id's of wellPanel's children.
To test the inputs you can simply use shiny::isTruthy:
library(shiny)
library(shinyjs)
library(htmltools)
ui <- fluidPage(
shinyjs::useShinyjs(),
wellPanel(
id = "wP1",
fluidRow(
column(
width = 4,
selectInput(
inputId = "input1",
label = "Input 1",
choices = letters[1:3]
)
),
column(
width = 4,
textInput(
inputId = "input2",
label = "Input 2",
placeholder = "Enter name"
)
),
column(
width = 4,
selectInput(
inputId = "input3",
label = "Input 3",
choices = c("", letters[4:6])
)
)
)
),
fluidRow(
column(
width = 12,
align = "center",
actionButton(
inputId = "actionbtn",
label = "Calculate",
class = "btn-success"
)
)
)
)
wP1Containers <- tagQuery(ui)$find("#wP1")$find("div.shiny-input-container")
wP1InputTags <- c(wP1Containers$find("input")$selectedTags(), wP1Containers$find("select")$selectedTags())
wP1InputIDs <- sapply(wP1InputTags, tagGetAttribute, attr = "id")
server <- function(input, output, session) {
observe({
valid_inputs <- all(sapply(wP1InputIDs, function(x){isTruthy(input[[x]])}))
shinyjs::toggleState(
id = "actionbtn",
condition = valid_inputs
)
})
}
shinyApp(ui, server)
Here is a related issue.
Another approach would be to use a prefix or suffix to identify those input ID's in session$input via grep and check if isTruthy via lapply.