diff --git a/src/backupformat/tgz.js b/src/backupformat/tgz.js
index b90057d1c..12b7ca446 100644
--- a/src/backupformat/tgz.js
+++ b/src/backupformat/tgz.js
@@ -35,6 +35,10 @@ function getBackupFilePath(backupConfig, remotePath) {
 }
 
 function addToPack(pack, header, options) {
+    assert.strictEqual(typeof pack, 'object');
+    assert.strictEqual(typeof header, 'object');
+    assert.strictEqual(typeof options, 'object'); // { input }
+
     return new Promise((resolve, reject) => {
         const packEntry = safe(() => pack.entry(header, function (error) {
             if (error) {
@@ -46,13 +50,9 @@ function addToPack(pack, header, options) {
             }
         }));
 
-        if (!packEntry) {
-            return reject(new BoxError(BoxError.FS_ERROR, `Failed to add ${header.name}: ${safe.error.message}`));
-        }
+        if (!packEntry) return reject(new BoxError(BoxError.FS_ERROR, `Failed to add ${header.name}: ${safe.error.message}`));
 
-        if (options?.input) {
-            safe(stream.pipeline(options.input, packEntry), { debug }); // background. rely on pack.entry callback for promise completion
-        }
+        if (options?.input) safe(stream.pipeline(options.input, packEntry), { debug }); // background. rely on pack.entry callback for promise completion
     });
 }