diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 0000000..3200758
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1,33 @@
+.*
+node_modules
+package-lock.json
+dist
+build
+*bundle*.js
+third_party
+
+/Octane/*
+/ARES-6/*
+/cdjs/*
+/8bitbench/*
+/class-fields/*
+/code-load/*
+/SunSpider
+/SeaMonster
+/WSL
+/worker/bomb-subtests
+/wasm/dotnet/build-*
+/wasm/tfjs-model-*
+/simple/*
+/generators/*
+/threejs/*
+
+# Ignore everything in RexBench, then selectively un-ignore.
+/RexBench/*
+!/RexBench/*/
+/RexBench/*/*
+!/RexBench/*/benchmark.js
+
+!benchmark.js
+!*/benchmark.js
+!/**/*.md
\ No newline at end of file
diff --git a/.prettierrc b/.prettierrc
new file mode 100644
index 0000000..fc20cfc
--- /dev/null
+++ b/.prettierrc
@@ -0,0 +1,12 @@
+{
+    "arrowParens": "always",
+    "bracketSameLine": false,
+    "bracketSpacing": true,
+    "htmlWhitespaceSensitivity": "css",
+    "printWidth": 100,
+    "semi": true,
+    "singleQuote": false,
+    "tabWidth": 4,
+    "trailingComma": "es5",
+    "useTabs": false
+}
diff --git a/package-lock.json b/package-lock.json
index 0d5639c..49699a5 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -21,7 +21,7 @@
                 "http-server": "^14.1.1",
                 "jsvu": "^2.5.1",
                 "local-web-server": "^5.4.0",
-                "prettier": "^2.8.3",
+                "prettier": "^2.8.8",
                 "selenium-webdriver": "^4.35.0"
             },
             "engines": {
@@ -4923,6 +4923,7 @@
             "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.8.8.tgz",
             "integrity": "sha512-tdN8qQGvNjw4CHbY+XXk0JgCXn9QiF21a55rBe5LJAU+kDyC4WQn4+awm2Xfk2lQMk5fKup9XgzTZtGkjBdP9Q==",
             "dev": true,
+            "license": "MIT",
             "bin": {
                 "prettier": "bin-prettier.js"
             },
diff --git a/package.json b/package.json
index 7ce9571..0223b9f 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,7 @@
         "compress": "node utils/compress.mjs",
         "lint:check": "eslint **/*.{js,mjs,jsx,ts,tsx}",
         "pretty:check": "prettier --check ./",
+        "pretty:format": "prettier --write ./",
         "format:check": "npm run pretty:check && npm run lint:check",
         "test:chrome": "node tests/run.mjs --browser chrome",
         "test:firefox": "node tests/run.mjs --browser firefox",
@@ -42,7 +43,7 @@
         "http-server": "^14.1.1",
         "jsvu": "^2.5.1",
         "local-web-server": "^5.4.0",
-        "prettier": "^2.8.3",
+        "prettier": "^2.8.8",
         "selenium-webdriver": "^4.35.0"
     }
 }