feat: check tile providers in addProviderTiles()

NEWS.md

@@ -2,6 +2,8 @@
 
 * Color palette improvements. All color palette functions now support all `{viridisLite}` palettes ("magma", "inferno", "plasma", "viridis", "cividis", "rocket", "mako", and "turbo").
 
+* `addProviderTiles()` will now error if the chosen `provider` does not match any currently loaded provider (by default, those in `providers`). This behaviour can be toggled off by setting the new `.check` argument to `FALSE` (@jack-davison, #929)
+
 # leaflet 2.2.2
 
 * Fixed #893: Correctly call `terra::crs()` when checking the CRS of a `SpatVector` object in `pointData()` or `polygonData()` (thanks @mkoohafkan, #894).

R/plugin-providers.R

@@ -19,10 +19,12 @@ leafletProviderDependencies <- function() {
 #'   <https://github.com/leaflet-extras/leaflet-providers>)
 #' @param layerId the layer id to assign
 #' @param group the name of the group the newly created layers should belong to
-#'   (for [clearGroup()] and [addLayersControl()] purposes).
-#'   Human-friendly group names are permitted--they need not be short,
-#'   identifier-style names.
+#'   (for [clearGroup()] and [addLayersControl()] purposes). Human-friendly
+#'   group names are permitted--they need not be short, identifier-style names.
 #' @param options tile options
+#' @param check Check that the specified `provider` matches the available
+#'   currently loaded leaflet providers? Defaults to `TRUE`, but can be toggled
+#'   to `FALSE` for advanced users.
 #' @return modified map object
 #'
 #' @examples
@@ -36,8 +38,19 @@ addProviderTiles <- function(
   provider,
   layerId = NULL,
   group = NULL,
-  options = providerTileOptions()
+  options = providerTileOptions(),
+  check = TRUE
 ) {
+  if (check) {
+    loaded_providers <- leaflet.providers::providers_loaded()
+    if (!provider %in% names(loaded_providers$providers)) {
+      stop(
+        "Unknown tile provider '",
+        provider,
+        "'; either use a known provider or pass `check = FALSE` to `addProviderTiles()`"
+      )
+    }
+  }
   map$dependencies <- c(map$dependencies, leafletProviderDependencies())
   invokeMethod(map, getMapData(map), "addProviderTiles",
     provider, layerId, group, options)

tests/testthat/test-tiles.R

@@ -0,0 +1,14 @@
+
+testthat::test_that("Checking of tile providers works correctly", {
+  expect_no_error(
+    leaflet() %>% addProviderTiles(providers[[1]])
+  )
+
+  expect_no_error(
+    leaflet() %>% addProviderTiles("FAKETILESET123", check = FALSE)
+  )
+
+  expect_error(
+    leaflet() %>% addProviderTiles("FAKETILESET123")
+  )
+})