diff --git a/package.json b/package.json
index e811b26..6294084 100644
--- a/package.json
+++ b/package.json
@@ -15,6 +15,10 @@
     "start": "node src/index.js"
   },
   "devDependencies": {
-    "jest": "^23.6.0"
+    "jest": "^23.6.0",
+    "prettier": "^1.16.4"
+  },
+  "prettier": {
+    "trailingComma": "es5"
   }
 }
diff --git a/yarn.lock b/yarn.lock
index 8d8e12e..118396b 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2937,6 +2937,11 @@ preserve@^0.2.0:
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
   integrity sha1-gV7R9uvGWSb4ZbMQwHE7yzMVzks=
 
+prettier@^1.16.4:
+  version "1.16.4"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.16.4.tgz#73e37e73e018ad2db9c76742e2647e21790c9717"
+  integrity sha512-ZzWuos7TI5CKUeQAtFd6Zhm2s6EpAD/ZLApIhsF9pRvRtM1RFo61dM/4MSRUA0SuLugA/zgrZD8m0BaY46Og7g==
+
 pretty-format@^23.6.0:
   version "23.6.0"
   resolved "https://registry.yarnpkg.com/pretty-format/-/pretty-format-23.6.0.tgz#5eaac8eeb6b33b987b7fe6097ea6a8a146ab5760"