Use double dashes for nesting

Reduce chance of collision, make it clearer

Author: David Heinemeier Hansson

lib/importmap/packager.rb

@@ -121,6 +121,6 @@ def vendored_package_path(package)
     end
 
     def package_filename(package)
-      "#{package.gsub("/", "-")}.js"
+      "#{package.gsub("/", "--")}.js"
     end
 end

test/packager_integration_test.rb

@@ -23,12 +23,16 @@ class Importmap::PackagerIntegrationTest < ActiveSupport::TestCase
     Importmap::Packager.endpoint = original_endpoint
   end
 
-  test "successful download from live service" do
+  test "successful downloads from live service" do
     Dir.mktmpdir do |vendor_dir|
       @packager = Importmap::Packager.new \
         Rails.root.join("config/importmap.rb"),
         vendor_path: Pathname.new(vendor_dir)
 
+      @packager.download("@github/webauthn-json",
+        "https://ga.jspm.io/npm:@github/[email protected]/dist/main/webauthn-json.js")
+      assert File.exist?(Pathname.new(vendor_dir).join("@github--webauthn-json.js"))
+
       @packager.download("react", "https://ga.jspm.io/npm:[email protected]/index.js")
       assert File.exist?(Pathname.new(vendor_dir).join("react.js"))