diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 0000000000..2c6562b20e
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1 @@
+test/common/ably-common/
diff --git a/package.json b/package.json
index 0a8dfbf4c2..efda4f0174 100644
--- a/package.json
+++ b/package.json
@@ -99,8 +99,8 @@
     "lint:fix": "eslint --fix .",
     "check-closure-compiler": "grunt check-closure-compiler",
     "prepare": "npm run build",
-    "format": "prettier --write --ignore-path .gitignore src test ably.d.ts webpack.config.js Gruntfile.js scripts/cdn_deploy.js docs/chrome-mv3.md",
-    "format:check": "prettier --check --ignore-path .gitignore src test ably.d.ts webpack.config.js Gruntfile.js scripts/cdn_deploy.js",
+    "format": "prettier --write --ignore-path .gitignore --ignore-path .prettierignore src test ably.d.ts webpack.config.js Gruntfile.js scripts/cdn_deploy.js docs/chrome-mv3.md",
+    "format:check": "prettier --check --ignore-path .gitignore --ignore-path .prettierignore src test ably.d.ts webpack.config.js Gruntfile.js scripts/cdn_deploy.js",
     "sourcemap": "source-map-explorer build/ably.min.js",
     "sourcemap:noencryption": "source-map-explorer build/ably.noencryption.min.js",
     "docs": "typedoc --entryPoints ably.d.ts --out docs/generated/default --readme docs/landing-pages/default.md && typedoc --entryPoints promises.d.ts --out docs/generated/promises --name \"ably (Promise-based)\" --readme docs/landing-pages/promises.md && cp docs/landing-pages/choose-library.html docs/generated/index.html"