diff --git a/externs.js b/externs.js
new file mode 100644
index 0000000..7588834
--- /dev/null
+++ b/externs.js
@@ -0,0 +1,11 @@
+/* Things which should not get renamed when compiling ClojureScript */
+
+/* this block relates to the use of Leaflet */
+var L = {
+    "map": {
+    "setView": function(){}
+    },
+    "tileLayer": {
+    "addTo": function(){}
+    }
+};