Allow for custom cache keys (#88)

Author: dhh

lib/importmap/map.rb

@@ -32,14 +32,23 @@ def pin_all_from(dir, under: nil, to: nil, preload: false)
     @directories[dir] = MappedDir.new(dir: dir, under: under, path: to, preload: preload)
   end
 
-  def preloaded_module_paths(resolver:)
-    cache_as(:preloaded_module_paths) do
+  # Returns an array of all the resolved module paths of the pinned packages. The `resolver` must respond to `asset_path`,
+  # such as `ActionController::Base.helpers` or `ApplicationController.helpers`. You'll want to use the resolver that has
+  # been configured for the `asset_host` you want these resolved paths to use. In case you need to resolve for different
+  # asset hosts, you can pass in a custom `cache_key` to vary the cache used by this method for the different cases.
+  def preloaded_module_paths(resolver:, cache_key: :preloaded_module_paths)
+    cache_as(cache_key) do
       resolve_asset_paths(expanded_preloading_packages_and_directories, resolver: resolver).values
     end
   end
 
-  def to_json(resolver:)
-    cache_as(:json) do
+  # Returns a JSON hash (as a string) of all the resolved module paths of the pinned packages in the import map format.
+  # The `resolver` must respond to `asset_path`, such as `ActionController::Base.helpers` or `ApplicationController.helpers`.
+  # You'll want to use the resolver that has been configured for the `asset_host` you want these resolved paths to use.
+  # In case you need to resolve for different asset hosts, you can pass in a custom `cache_key` to vary the cache used
+  # by this method for the different cases.
+  def to_json(resolver:, cache_key: :json)
+    cache_as(cache_key) do
       JSON.pretty_generate({ "imports" => resolve_asset_paths(expanded_packages_and_directories, resolver: resolver) })
     end
   end