diff --git a/.prettierrc b/.prettierrc
index 19d94ee..7d955c2 100644
--- a/.prettierrc
+++ b/.prettierrc
@@ -2,5 +2,6 @@
   "semi": false,
   "arrowParens": "always",
   "singleQuote": true,
-  "printWidth": 110
+  "printWidth": 110,
+  "trailingComma": "all"
 }
diff --git a/src/merkleTree.js b/src/merkleTree.js
index a569123..2f2511c 100644
--- a/src/merkleTree.js
+++ b/src/merkleTree.js
@@ -49,7 +49,7 @@ class MerkleTree {
           this._layers[level - 1][i * 2],
           i * 2 + 1 < this._layers[level - 1].length
             ? this._layers[level - 1][i * 2 + 1]
-            : this._zeros[level - 1]
+            : this._zeros[level - 1],
         )
       }
     }
@@ -102,7 +102,7 @@ class MerkleTree {
         this._layers[level - 1][index * 2],
         index * 2 + 1 < this._layers[level - 1].length
           ? this._layers[level - 1][index * 2 + 1]
-          : this._zeros[level - 1]
+          : this._zeros[level - 1],
       )
     }
   }