Delete and auto-populate rows

gistfile1.txt

library(shiny)
library(shinyjs)
library(glue)


ui <- fluidPage(
  actionButton('delete_all', label = "Delete All"),
  actionButton('auto_populate', label = "Auto Populate"),
  tagList(
    shinyalert::useShinyalert(),
    shinyjs::useShinyjs(),
    fluidRow(
      column(2, h5("Variable Name"))
    ),
    tags$div(id = "RowPlaceholder")
  )
)

server <- function(input, output, session) {
  
  current_rows <- reactiveVal()
  num <- reactiveVal(0)
  
  insert_row <- function(num, varname_value = NULL) {
    
    num(num()+1)
    current_rows( c(current_rows(), num()) )
    
    row_id               <- glue::glue("row_{num()}")
    varname_id           <- glue::glue("var_name_{num()}")
    delete_btn_id        <- glue::glue("delete_{num()}")
    
    row <- fluidRow(
      id = row_id,
      column(2, textInput(varname_id, label = NULL, 
                          value = varname_value, width = "100%")),
      fluidRow(
        shiny::actionButton(delete_btn_id, label = NULL, 
                            icon = shiny::icon("trash-alt"), width = '40px')
      )
    )
    
    insertUI(
      selector = glue::glue("#{'RowPlaceholder'}"),
      where = "beforeEnd",
      ui = row, 
      immediate = TRUE
    )
    
    observeEvent(input[[delete_btn_id]],{ 
      
      delete_row_number <- stringi::stri_split_fixed(
        delete_btn_id, "delete_", omit_empty=TRUE, simplify=TRUE)
      delete_row_number <- as.numeric(delete_row_number)
      
      delete_row(delete_row_number)
      
    }, once = TRUE, ignoreInit = TRUE, priority = 2) 
    
  }
  
  delete_row <- function(delete_row_number) {
    
    row_id               <- glue::glue("row_{delete_row_number}")
    delete_btn_id        <- glue::glue("delete_{delete_row_number}")
    
    removeUI(selector = glue::glue("#{row_id}"), immediate = TRUE)
    
    shinyjs::runjs(glue::glue("Shiny.onInputChange(‘{delete_btn_id}’, null)"))
    
    current_rows(
      current_rows()[-match(delete_row_number, current_rows())]
    )
  }
  
  observeEvent(input$delete_all, {
    
    lapply(current_rows(), function(row_number){
      
      delete_id <- glue::glue('delete_{row_number}')
      delete_btn_to_click <- glue::glue('{delete_id}')
      shinyjs::click(delete_btn_to_click)
      
    })
    
    num(0)
    
  })
  
  observeEvent(input$auto_populate,{
    
    lapply(current_rows(), function(row_number){
      
      delete_id <- glue::glue('delete_{row_number}')
      delete_btn_to_click <- glue::glue('{delete_id}')
      shinyjs::click(delete_btn_to_click)
      
    })
    
    if (length(current_rows()) == 0 | is.null(current_rows())){
      if(isTruthy(input$auto_populate)){
        
        current_rows <- reactiveVal()
        num(0)
        
        instructions <- c("row1", "row2")
        lapply(instructions, function(x){
          insert_row(num, varname_value = x)
          num(num()+1)
        })
      }
    }
    
  })
}

shinyApp(ui, server)