diff --git a/Rakefile b/Rakefile
index 571f274103d292cd681b0660b3b29a93cf2de60b..62a7de5e594ef85aee7f0968241a9dd8392c6b2f 100644
--- a/Rakefile
+++ b/Rakefile
@@ -198,6 +198,7 @@ class JsDuckRunner
       "--categories", "#{@sdk_dir}/touch/doc-resources/categories.json",
       "--videos", "#{@sdk_dir}/touch/doc-resources/videos.json",
       "--output", "#{@out_dir}",
+      "--external=google.maps.Map,google.maps.LatLng",
       "#{@sdk_dir}/touch/src/core",
       "#{@sdk_dir}/touch/src/data",
       "#{@sdk_dir}/touch/src/gestures",