R/as.json.R

In ropensci/geojsonio: Convert Data from and to 'GeoJSON' or 'TopoJSON'

#' Convert inputs to JSON
#'
#' @export
#' @param x Input
#' @param ... Further args passed on to [jsonlite::toJSON()]
#' @details when the output of [topojson_list()] is given to
#' this function we use a special internal fxn `astjl()` to
#' parse the object - see that fxn and let us know if any
#' problems you run in to
#' @examples \dontrun{
#' (res <- geojson_list(us_cities[1:2, ], lat = "lat", lon = "long"))
#' as.json(res)
#' as.json(res, pretty = TRUE)
#'
#' vec <- c(-99.74, 32.45)
#' as.json(geojson_list(vec))
#' as.json(geojson_list(vec), pretty = TRUE)
#' }
as.json <- function(x, ...) {
  UseMethod("as.json")
}

#' @export
as.json.list <- function(x, ...) {
  if ("arcs" %in% names(x)) {
    return(astjl(x))
  }
  to_json(x, ...)
}

#' @export
as.json.geo_list <- function(x, ...) to_json(unclass(x), ...)

#' @export
as.json.geojson_file <- function(x, ...) {
  res <- as.SpatialPolygonsDataFrame(x, ...)
  to_json(unclass(spdftogeolist(res)), ...)
}

#' @export
as.json.character <- function(x, ...) {
  res <- as.SpatialPolygonsDataFrame(x, ...)
  to_json(unclass(spdftogeolist(res)), ...)
}

astjl <- function(x) {
  for (i in seq_along(x$objects[[1]]$geometries)) {
    if ("arcs" %in% names(x$objects[[1]]$geometries[[i]])) {
      x$objects[[1]]$geometries[[i]]$arcs <-
        jsonlite::toJSON(x$objects[[1]]$geometries[[i]]$arcs,
          digits = 7, auto_unbox = FALSE, force = TRUE
        )
    }
  }
  jsonlite::toJSON(x,
    digits = 7, auto_unbox = TRUE, force = TRUE,
    json_verbatim = TRUE
  )
}