diff --git a/.gitignore b/.gitignore
index a51ee16..8f7d857 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,8 @@ spec/rails/rails-*
 pkg
 .bundle
 vendor/bundl
+
+# Built by the `prepare`/`prepublishOnly` npm scripts (copied from app/assets);
+# generated on install, never committed.
+/src/
+*.bak
diff --git a/package.json b/package.json
index ad9bd58..f0ef781 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,7 @@
   "scripts": {
     "prepare_src": "rm -rf src && cp -R app/assets/javascripts/ src && cp -R app/assets/stylesheets/ src",
     "prepare_import": "sed -i.bak 1s/'\\/\\/\\= require vendor\\/jquery.datetimepicker.full'/\"import '.\\/vendor\\/jquery.datetimepicker.full';\"/ src/active_admin_datetimepicker.js",
+    "prepare": "npm run prepare_src && npm run prepare_import",
     "prepublishOnly": "npm run prepare_src && npm run prepare_import"
   },
   "dependencies": {