diff --git a/.drone.yml b/.drone.yml
index 5d4ab2ca96..5cfba60cd4 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -19,6 +19,13 @@ pipeline:
     when:
       matrix:
         TESTS: check-autoloader
+  check-mergejs:
+    image: nextcloudci/php7.0:php7.0-7
+    commands:
+      - bash ./build/mergejschecker.sh
+    when:
+      matrix:
+        TESTS: check-mergejs
   app-check-code:
     image: nextcloudci/php7.0:php7.0-7
     commands:
@@ -493,6 +500,7 @@ matrix:
     - TESTS: integration-ldap-features
     - TESTS: jsunit
     - TESTS: check-autoloader
+    - TESTS: check-mergejs
     - TESTS: app-check-code
     - TESTS: syntax-php5.6
     - TESTS: syntax-php7.0
diff --git a/build/mergejschecker.sh b/build/mergejschecker.sh
new file mode 100755
index 0000000000..a8c5c37a1f
--- /dev/null
+++ b/build/mergejschecker.sh
@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+
+#Regenerate the vendors core.js
+echo
+echo "Regenerating core/vendor/core.js"
+
+d=`dirname $(readlink -f $0)`
+
+php $d/mergejs.php
+
+files=`git diff --name-only`
+
+for file in $files
+do
+    if [[ $file == core/vendor/core.js ]]
+    then
+        echo "The merged vendor file is not up to date"
+        echo "Please run: php build/mergejs.php"
+        echo "And commit the result"
+        exit 1
+        break
+    fi
+done
+
+echo "Vendor js merged as expected. Carry on"
+exit 0