Using input$myInput to pass to a placeholder in textAreaInput() in Shiny-CodePudding

I am trying to pass the "language" text to a placeholder in the textAreaInput. I want to pass the input$selectLanguage to the textArea and the placeholder text to change depending on the language selected.

App:

library(shiny)

# Define UI for application that draws a histogram
ui <- fluidPage(
    selectInput("selectLanguage", "What language ?", choices = c("EN", "ES", "FR")),
    textAreaInput(inputId = "desc", label = "Describe yourself in a few words", width = '100%', rows = 4, placeholder = "emailPlaceholder"),

)

# Define server logic required to draw a histogram
server <- function(input, output) {

    ########################## Add placeholder #############################
    emailPlaceholder = reactive({
        emailDescPlaceholder = paste("In ", input$selectLanguage, " write about yourself: ")
    })
    output$emailPlaceholder = renderText({
        emailPlaceholder()
    })
}

# Run the application
shinyApp(ui = ui, server = server)

Expected output:

In "EN" write about yourself:
In "ES" write about yourself:
In "FR" write about yourself:

Solution:

library(shiny)

# Define UI for application that draws a histogram
ui <- fluidPage(
    selectInput("selectLanguage", "What language ?", choices = c("EN", "ES", "FR")),
    textAreaInput(inputId = "desc", label = "Describe yourself in a few words", width = '100%', rows = 4)

)

# Define server logic required to draw a histogram
server <- function(input, output, session) {

    ########################## Add placeholder #############################
    observe({
        updateTextAreaInput(session, "desc",
            placeholder = paste("In ", input$selectLanguage, " write about yourself: ")
        )

    })
}

# Run the application
shinyApp(ui = ui, server = server)

CodePudding user response：

Use updateTextAreaInput() with placeholder parameter.

https://www.rdocumentation.org/packages/shiny/versions/1.7.3/topics/updateTextAreaInput

CodePudding user response：

This solved my issue:

library(shiny)

# Define UI for application that draws a histogram
ui <- fluidPage(
    selectInput("selectLanguage", "What language ?", choices = c("EN", "ES", "FR")),
    textAreaInput(inputId = "desc", label = "Describe yourself in a few words", width = '100%', rows = 4)

)

# Define server logic required to draw a histogram
server <- function(input, output, session) {

    ########################## Add placeholder #############################
    observe({
        updateTextAreaInput(session, "desc",
            placeholder = paste("In ", input$selectLanguage, " write about yourself: ")
        )

    })
}

# Run the application
shinyApp(ui = ui, server = server)