R/zzz.R

In geanders/noaastormevents: Explore NOAA Storm Events Database

.pkgenv <- new.env(parent=emptyenv())

.onLoad  <- function(libname, pkgname) {
  has_data <- requireNamespace("hurricaneexposuredata", quietly = TRUE)
  .pkgenv[["has_data"]] <- has_data
}

.onAttach <- function(libname, pkgname) {
  if (!.pkgenv$has_data) {
    msg <- paste("To use this package in conjunction with hurricane tracks,",
                 "you must install the",
                 "hurricaneexposuredata package. To install that ",
                 "package, run `install.packages('hurricaneexposuredata',",
                 "repos='https://geanders.github.io/drat/', type='source')`.",
                 "See the `noaastormevents` vignette for more details.")
    msg <- paste(strwrap(msg), collapse="\n")
    packageStartupMessage(msg)
  }
}

hasData <- function(has_data = .pkgenv$has_data) {
  if (!has_data) {
    msg <- paste("To use this function with a specific hurricane, you must have the",
                 "`hurricaneexposuredata` package installed. See the",
                 "`noaastormevents` package vignette for more details.")
    msg <- paste(strwrap(msg), collapse="\n")
    message(msg)
    return(invisible(NULL))
  }
}