R/check_installed_package.R

In vvmover: Read and Write Data

#' check_installed_package
#'
#' Check if a package is installed. If not,
#' throw an error message
#'
#' @param package_name the name of the package (quoted)
#' @param check the function should work as a boolean operator
#' @return Boolean value whether package is installed.
#' @examples
#' check_installed_package("dplyr")
#'
#' @export
check_installed_package <- function(package_name, check = FALSE) {
  if (check) {
    if (!requireNamespace(package_name, quietly = TRUE)) {
      return(FALSE)
    } else {
      return(TRUE)
    }
  } else {
    if (!requireNamespace(package_name, quietly = TRUE)) {
      stop(
        paste(
          "Package", package_name, "required to use this function",
          "install this:", paste0("\ninstall.packages(\"", package_name, "\")")
        ),
        call. = FALSE
      )
    }
  }
}