Error in x$slide : $ operator is invalid for atomic vectors, when calling pipelined functions with passing arguments

I have this code for making a ppt from R:

library(officer)
library(tidyverse)

pres <- read_pptx("E:/Some folder/Document.pptx") 

title_slide_2 <- "Trial"
subtitle_slide_2 <- "Some subtitle"
paragraph_slide_2 <- "Something"

#function for making a placeholder
ph <- function(x,ph_value,ph_name){   
  ph_with(x,value = ph_value, location = ph_location_label(ph_label = ph_name))  
}
  
placeholder <- function(title = NULL,
                        subtitle = NULL,
                        table = NULL,
                        ul = NULL){
  
  if(!is.null(title)){  
    ph_title <- ph(title, "Title")
  }
  if(!is.null(subtitle)){  
    ph_subtitle <- ph(subtitle, "Subtitle")
  }  
  if(!is.null(table)){  
    ph_table <- ph(table, "Table")
  } 
  if(!is.null(ul)){  
    ph_ul <- ph(ul, "List")
  } 
  
  placeholders <- ph_title %>% 
                  ph_subtitle %>% 
                  ph_table %>%
                  ph_paragraph_1 %>%
                  ph_paragraph_2 %>%
                  ph_paragraph_3 %>%
                  ph_paragraph_4 %>%
                  ph_paragraph_5 %>%
                  ph_ul %>%
                  ph_picture_1 %>%
                  ph_picture_2 %>%
                  ph_abbreviations_1 %>%
                  ph_abbreviations_2 %>%
                  ph_headline_capture
    
    return(placeholders) 
}

my_pres <- pres %>%
  remove_slide(index = 1) %>%    
  add_slide(layout = "Slide 2", master = "Office Theme") %>%                                     
  placeholder(title = title_slide_2, subtitle_1 = subtitle_slide_2, paragraph_1 = paragraph_slide_2)
 
print(my_pres, glue::glue("Doc trial.pptx"))   
  

and it shows me an error stating: Error in x$slide : $ operator is invalid for atomic vectors.

Does anyone have any suggestions on how to change this code? I don't know whether it is ok to make a function for placeholders this way, and whether I made a proper calling of that function, along with passing the arguments

There are several issues with your code. After some refactoring here is a working minimal reproducible example using the default pptx template shipped with officer:

library(officer)

pres <- read_pptx()

title_slide_2 <- "Trial"
subtitle_slide_2 <- "Some subtitle"

ph <- function(x, ph_value, ph_name) {
  ph_with(x, value = ph_value, location = ph_location_label(ph_label = ph_name))
}

placeholder <- function(x,
                        title = NULL,
                        subtitle = NULL,
                        table = NULL,
                        ul = NULL) {
  ph_title <- \(x)  if (!is.null(title)) ph(x, title, "Title 1") else x
  
  ph_subtitle <- \(x)  if (!is.null(subtitle)) ph(x, subtitle, "Content Placeholder 2") else x
  
  ph_table <- \(x)  if (!is.null(table)) ph(x, table, "Content Placeholder 3") else x

  x |> 
    ph_title() |> 
    ph_subtitle() |> 
    ph_table()
}

my_pres <- pres |> 
  #remove_slide(index = 1) %>%
  add_slide(layout = "Two Content", master = "Office Theme") |>
  placeholder(
    title = title_slide_2, 
    subtitle = subtitle_slide_2
  )

print(my_pres, "Doc trial.pptx")