Generate outline for {xaringan} presentations

xaringan_outliner.R

# Load relevant packages
library(purrr)
library(stringr)
library(glue)


#' Programmatically generate xaringan outline
#'
#' @param file string name of generated xaringan RMarkdown
#' @param ... list of objects containing the structure for the presentation
#'
#' @example
#' outline_pres(sec_1 = list(title = "Intros", n_slides = 3),
#'              sec_2 = list(title = "Part A", n_slides = 5))
outline_pres <- function(file = "untitled.Rmd", ...) {
  header <- '---
title: "Presentation Ninja"
author: "Yihui Xie"
institute: "RStudio, PBC"
date: "2016/12/12 (updated: `r Sys.Date()`)"
output:
  xaringan::moon_reader:
    lib_dir: libs
    nature:
      highlightStyle: github
      highlightLines: true
      countIncrementalSlides: false
---
  '
  input <- list(...)
  template <- map(input, process_sections)

  fileConn <- file(file)
  writeLines(str_c(c(header, template)), fileConn)
  close(fileConn)

  # Open file in RStudio
  file.edit(file)
}


#' Process list configuration of slide structure
#'
#' @param config list with parameters `title` as string for the name of the
#'   section and `n_slides` as an integer for the number of slides in this
#'   section
#'
#' @return string
#' @export
#'
#' @examples
#' process_sections(list(title = "Section Name", n_slides = 3))
process_sections <- function(config) {
  # Process input
  section_name <- config$title
  n_slides <- config$n_slides

  # Template components
  section <- glue("# {section_name}")
  divider <- "---"
  slide_heading <- "## Title"
  collapse <- "\n\n"

  # Create individual slides
  slide_struc <- c(slide_heading, "", divider)
  slides <- replicate(n_slides, str_c(slide_struc, collapse = collapse))

  # Put slides and section title together
  section_struc <- c(section, divider, slides, "")
  section_txt <- str_c(section_struc, collapse = collapse)

  return(section_txt)
}