diff --git a/doc/tutorials/closure.md b/doc/tutorials/closure.md
index 6e3f26cafd..27f0fea743 100644
--- a/doc/tutorials/closure.md
+++ b/doc/tutorials/closure.md
@@ -172,6 +172,7 @@ The minimum config file looks like this:
       "ol.ENABLE_WEBGL=false"
     ],
     "js": [
+      "node_modules/openlayers/src/ol/typedefs.js",
       "node_modules/openlayers/externs/olx.js",
       "node_modules/openlayers/externs/oli.js"
     ],
@@ -223,6 +224,7 @@ Here is a version of `config.json` with more compilation checks enabled:
       "ol.ENABLE_WEBGL=false"
     ],
     "js": [
+      "node_modules/openlayers/src/ol/typedefs.js",
       "node_modules/openlayers/externs/olx.js",
       "node_modules/openlayers/externs/oli.js"
     ],