diff --git a/examples/mainnet-poll/package.json b/examples/mainnet-poll/package.json
index 1cd2352..2150c14 100644
--- a/examples/mainnet-poll/package.json
+++ b/examples/mainnet-poll/package.json
@@ -47,6 +47,7 @@
     "jsdom-global": "^3.0.2",
     "mocha": "^9.0.3",
     "npm-watch": "^0.11.0",
+    "prettier": "^2.5.1",
     "process": "^0.11.10",
     "rimraf": "^3.0.2",
     "ts-node": "^10.1.0",
diff --git a/examples/mainnet-poll/yarn.lock b/examples/mainnet-poll/yarn.lock
index 380d21a..22f6b4f 100644
--- a/examples/mainnet-poll/yarn.lock
+++ b/examples/mainnet-poll/yarn.lock
@@ -6715,6 +6715,11 @@ prepend-http@^2.0.0:
   resolved "https://registry.yarnpkg.com/prepend-http/-/prepend-http-2.0.0.tgz#e92434bfa5ea8c19f41cdfd401d741a3c819d897"
   integrity sha1-6SQ0v6XqjBn0HN/UAddBo8gZ2Jc=
 
+prettier@^2.5.1:
+  version "2.5.1"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-2.5.1.tgz#fff75fa9d519c54cf0fce328c1017d94546bc56a"
+  integrity sha512-vBZcPRUR5MZJwoyi3ZoyQlc1rXeEck8KgeC9AwwOn+exuxLxq5toTRDTSaVrXHxelDMHy9zlicw8u66yxoSUFg==
+
 pretty-error@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/pretty-error/-/pretty-error-4.0.0.tgz#90a703f46dd7234adb46d0f84823e9d1cb8f10d6"