diff --git a/lib/workers/branch/lock-files.js b/lib/workers/branch/lock-files.js
index 236125de19292240172913f958b0e92587124192..f7e1ce31337426aef6eaf1fa593ca62900a684c9 100644
--- a/lib/workers/branch/lock-files.js
+++ b/lib/workers/branch/lock-files.js
@@ -106,7 +106,12 @@ function determineLockFileDirs(config) {
           shrinkwrapYamlDirs.push(dirname);
         }
       }
-      return { packageLockFileDirs, yarnLockFileDirs, shrinkwrapYamlDirs };
+      return {
+        packageLockFileDirs,
+        npmShrinkwrapDirs,
+        yarnLockFileDirs,
+        shrinkwrapYamlDirs,
+      };
     }
   }
 
diff --git a/test/workers/branch/__snapshots__/lock-files.spec.js.snap b/test/workers/branch/__snapshots__/lock-files.spec.js.snap
index 4e213fe4c0238601a7addd6da827e0d02e133ba4..a3ca791d4c827a20f22117341bfb354a24730270 100644
--- a/test/workers/branch/__snapshots__/lock-files.spec.js.snap
+++ b/test/workers/branch/__snapshots__/lock-files.spec.js.snap
@@ -2,6 +2,9 @@
 
 exports[`workers/branch/lock-files determineLockFileDirs returns all directories if lock file maintenance 1`] = `
 Object {
+  "npmShrinkwrapDirs": Array [
+    "leftend",
+  ],
   "packageLockFileDirs": Array [
     "backend",
   ],