diff --git a/externs.js b/externs.js
new file mode 100644
index 0000000..276bc34
--- /dev/null
+++ b/externs.js
@@ -0,0 +1,3 @@
+var $ = function(){};
+$.draggable = function(){};
+$.droppable = function(){};
diff --git a/project.clj b/project.clj
index 19a11c8..4d5193f 100644
--- a/project.clj
+++ b/project.clj
@@ -24,6 +24,7 @@
                              [lein-figwheel "0.5.4-7"]]
                    :dependencies [[reloaded.repl "0.2.2"]]
                    :source-paths ["dev"]
+                   :externs ["externs.js"]
                    :cljsbuild {:builds [{:id :main
                                          :source-paths ["src" "dev"]
                                          :figwheel true