diff --git a/src/loader.js b/src/loader.js
index 9801d590..7a5f0bdd 100644
--- a/src/loader.js
+++ b/src/loader.js
@@ -124,6 +124,9 @@ export function pitch(request) {
           };
         });
       }
+      if(typeof this[MODULE_TYPE] !== 'function') {
+        return callback(new Error('It seems you are using the loader but forgot to register the plugin'));
+      }
       this[MODULE_TYPE](text);
     } catch (e) {
       return callback(e);