diff --git a/.changeset/config.json b/.changeset/config.json
index 6b37255..42efc1c 100644
--- a/.changeset/config.json
+++ b/.changeset/config.json
@@ -1,11 +1,11 @@
 {
-  "$schema": "https://unpkg.com/@changesets/config@3.0.5/schema.json",
-  "changelog": "@changesets/cli/changelog",
-  "commit": false,
-  "fixed": [],
-  "linked": [],
-  "access": "restricted",
-  "baseBranch": "main",
-  "updateInternalDependencies": "patch",
-  "ignore": []
+	"$schema": "https://unpkg.com/@changesets/config@3.0.5/schema.json",
+	"changelog": "@changesets/cli/changelog",
+	"commit": false,
+	"fixed": [],
+	"linked": [],
+	"access": "restricted",
+	"baseBranch": "main",
+	"updateInternalDependencies": "patch",
+	"ignore": []
 }
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 564bcf3..28c1a1a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,6 +12,17 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: pnpm
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm lint
   Tests:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 15
@@ -30,7 +41,7 @@ jobs:
             os: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v3
         with:
@@ -46,7 +57,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: pnpm/action-setup@v4
       - uses: actions/setup-node@v3
         with:
diff --git a/.prettierignore b/.prettierignore
index ee43e2d..a73deb6 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -1,3 +1,8 @@
+pnpm-lock.yaml
+
 test/samples/*/*.js
 test/sandbox/_input.js
 test/sandbox/_output.js
+
+expected.ts
+expected.jsx
diff --git a/package.json b/package.json
index 0fa59ac..5112c7a 100644
--- a/package.json
+++ b/package.json
@@ -1,58 +1,61 @@
 {
-  "name": "esrap",
-  "version": "2.1.0",
-  "description": "Parse in reverse",
-  "repository": {
-    "type": "git",
-    "url": "git+https://github.com/sveltejs/esrap.git"
-  },
-  "type": "module",
-  "files": [
-    "src",
-    "types"
-  ],
-  "exports": {
-    ".": {
-      "types": "./types/index.d.ts",
-      "default": "./src/index.js"
-    },
-    "./languages/ts": {
-      "types": "./types/index.d.ts",
-      "default": "./src/languages/ts/index.js"
-    },
-    "./languages/tsx": {
-      "types": "./types/index.d.ts",
-      "default": "./src/languages/tsx/index.js"
-    }
-  },
-  "types": "./types/index.d.ts",
-  "devDependencies": {
-    "@changesets/cli": "^2.27.11",
-    "@sveltejs/acorn-typescript": "^1.0.5",
-    "@typescript-eslint/types": "^8.2.0",
-    "@vitest/ui": "^2.1.1",
-    "acorn": "^8.15.0",
-    "dts-buddy": "^0.6.2",
-    "prettier": "^3.0.3",
-    "typescript": "^5.7.2",
-    "vitest": "^2.1.1",
-    "zimmerframe": "^1.0.0"
-  },
-  "scripts": {
-    "changeset:version": "changeset version",
-    "changeset:publish": "changeset publish",
-    "check": "tsc",
-    "prepublishOnly": "pnpm test && dts-buddy -m esrap:./src/public.d.ts -m esrap/languages/ts:./src/languages/ts/public.d.ts -m esrap/languages/tsx:./src/languages/tsx/public.d.ts",
-    "sandbox": "node test/sandbox/index.js",
-    "test": "vitest --run",
-    "test:ui": "vitest --ui"
-  },
-  "license": "MIT",
-  "dependencies": {
-    "@jridgewell/sourcemap-codec": "^1.4.15"
-  },
-  "packageManager": "pnpm@9.8.0",
-  "publishConfig": {
-    "access": "public"
-  }
+	"name": "esrap",
+	"version": "2.1.0",
+	"description": "Parse in reverse",
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/sveltejs/esrap.git"
+	},
+	"type": "module",
+	"files": [
+		"src",
+		"types"
+	],
+	"exports": {
+		".": {
+			"types": "./types/index.d.ts",
+			"default": "./src/index.js"
+		},
+		"./languages/ts": {
+			"types": "./types/index.d.ts",
+			"default": "./src/languages/ts/index.js"
+		},
+		"./languages/tsx": {
+			"types": "./types/index.d.ts",
+			"default": "./src/languages/tsx/index.js"
+		}
+	},
+	"types": "./types/index.d.ts",
+	"devDependencies": {
+		"@changesets/cli": "^2.27.11",
+		"@jridgewell/sourcemap-codec": "^1.5.0",
+		"@sveltejs/acorn-typescript": "^1.0.5",
+		"@typescript-eslint/types": "^8.2.0",
+		"@vitest/ui": "^2.1.1",
+		"acorn": "^8.15.0",
+		"dts-buddy": "^0.6.2",
+		"prettier": "^3.0.3",
+		"typescript": "^5.7.2",
+		"vitest": "^2.1.1",
+		"zimmerframe": "^1.0.0"
+	},
+	"scripts": {
+		"changeset:version": "changeset version",
+		"changeset:publish": "changeset publish",
+		"check": "tsc",
+		"prepublishOnly": "pnpm test && dts-buddy -m esrap:./src/public.d.ts -m esrap/languages/ts:./src/languages/ts/public.d.ts -m esrap/languages/tsx:./src/languages/tsx/public.d.ts",
+		"sandbox": "node test/sandbox/index.js",
+		"test": "vitest --run",
+		"test:ui": "vitest --ui",
+		"format": "pnpm lint --write",
+		"lint": "prettier --check . --ignore-path .gitignore --ignore-path .prettierignore"
+	},
+	"license": "MIT",
+	"dependencies": {
+		"@jridgewell/sourcemap-codec": "^1.4.15"
+	},
+	"packageManager": "pnpm@9.8.0",
+	"publishConfig": {
+		"access": "public"
+	}
 }
diff --git a/test/samples/jsx-basic/expected.jsx b/test/samples/jsx-basic/expected.jsx
index 8830fe7..8425af8 100644
--- a/test/samples/jsx-basic/expected.jsx
+++ b/test/samples/jsx-basic/expected.jsx
@@ -1,6 +1,6 @@
 console.log(<>
-    <div>
-        <img src="cat.png" alt={"An image of a flying cat"} />
-        Time since last cat incident: {"5 days"}
-    </div>
-</>);
+		<div>
+			<img src="cat.png" alt={'An image of a flying cat'} />
+			Time since last cat incident: {'5 days'}
+		</div>
+	</>);
\ No newline at end of file
diff --git a/test/samples/jsx-basic/expected.jsx.map b/test/samples/jsx-basic/expected.jsx.map
index 06a812c..12adb48 100644
--- a/test/samples/jsx-basic/expected.jsx.map
+++ b/test/samples/jsx-basic/expected.jsx.map
@@ -5,7 +5,7 @@
     "input.js"
   ],
   "sourcesContent": [
-    "console.log(<>\n    <div>\n        <img src=\"cat.png\" alt={\"An image of a flying cat\"} />\n        Time since last cat incident: {\"5 days\"}\n    </div>\n</>)"
+    "console.log(\n\t<>\n\t\t<div>\n\t\t\t<img src=\"cat.png\" alt={'An image of a flying cat'} />\n\t\t\tTime since last cat incident: {'5 days'}\n\t\t</div>\n\t</>\n);\n"
   ],
-  "mappings": "AAAA,OAAO,CAAC,GAAG,GAAG;IACV,CAAC,GAAG,CAAC;QACD,CAAC,GAAG,CAAC,GAAG,CAAC,SAAS,CAAC,GAAG,EAAE,0BAA0B,IAAI;sCACxB,CAAC,QAAQ,CAAC;IAC5C,EAAE,GAAG,CAAC;AACV"
+  "mappings": "AAAA,OAAO,CAAC,GAAG,GACR;EACD,CAAC,GAAG,CAAC;GACJ,CAAC,GAAG,CAAC,GAAG,CAAC,SAAS,CAAC,GAAG,EAAE,0BAA0B,IAAI;iCACxB,CAAC,QAAQ,CAAC;EACzC,EAAE,GAAG,CAAC;CACP"
 }
\ No newline at end of file
diff --git a/test/samples/jsx-basic/input.jsx b/test/samples/jsx-basic/input.jsx
index 6ad284a..2d85f67 100644
--- a/test/samples/jsx-basic/input.jsx
+++ b/test/samples/jsx-basic/input.jsx
@@ -1,6 +1,8 @@
-console.log(<>
-    <div>
-        <img src="cat.png" alt={"An image of a flying cat"} />
-        Time since last cat incident: {"5 days"}
-    </div>
-</>)
\ No newline at end of file
+console.log(
+	<>
+		<div>
+			<img src="cat.png" alt={'An image of a flying cat'} />
+			Time since last cat incident: {'5 days'}
+		</div>
+	</>
+);
diff --git a/test/samples/ts-null-keyword/expected.ts.map b/test/samples/ts-null-keyword/expected.ts.map
index e61feb8..1783daa 100644
--- a/test/samples/ts-null-keyword/expected.ts.map
+++ b/test/samples/ts-null-keyword/expected.ts.map
@@ -5,7 +5,7 @@
     "input.js"
   ],
   "sourcesContent": [
-    "let a: string | null = null"
+    "let a: string | null = null;\n"
   ],
   "mappings": "IAAI,CAAgB,EAAb,MAAM,GAAG,IAAI,GAAG,IAAI"
 }
\ No newline at end of file
diff --git a/test/samples/ts-null-keyword/input.ts b/test/samples/ts-null-keyword/input.ts
index 5369a51..527fb62 100644
--- a/test/samples/ts-null-keyword/input.ts
+++ b/test/samples/ts-null-keyword/input.ts
@@ -1 +1 @@
-let a: string | null = null
\ No newline at end of file
+let a: string | null = null;
diff --git a/test/samples/ts-return-type/expected.ts.map b/test/samples/ts-return-type/expected.ts.map
index 3f78c09..75e9df4 100644
--- a/test/samples/ts-return-type/expected.ts.map
+++ b/test/samples/ts-return-type/expected.ts.map
@@ -5,7 +5,7 @@
     "input.js"
   ],
   "sourcesContent": [
-    "class Fields {\n\tstatic cuid(): string {\n\t\treturn 'random cuid...'\n\t}\n}\n"
+    "class Fields {\n\tstatic cuid(): string {\n\t\treturn 'random cuid...';\n\t}\n}\n"
   ],
   "mappings": "MAAM,MAAM,CAAC,CAAC;QACN,IAAI,IAAI,MAAM,CAAC,CAAC;SACf,gBAAgB;CACxB,CAAC;AACF,CAAC"
 }
\ No newline at end of file
diff --git a/test/samples/ts-return-type/input.ts b/test/samples/ts-return-type/input.ts
index 6de8f37..bcabe9f 100644
--- a/test/samples/ts-return-type/input.ts
+++ b/test/samples/ts-return-type/input.ts
@@ -1,5 +1,5 @@
 class Fields {
 	static cuid(): string {
-		return 'random cuid...'
+		return 'random cuid...';
 	}
 }
diff --git a/test/samples/ts-undefined-keyword/expected.ts.map b/test/samples/ts-undefined-keyword/expected.ts.map
index f133c38..a2af5c9 100644
--- a/test/samples/ts-undefined-keyword/expected.ts.map
+++ b/test/samples/ts-undefined-keyword/expected.ts.map
@@ -5,7 +5,7 @@
     "input.js"
   ],
   "sourcesContent": [
-    "let a: number | undefined\na = 2"
+    "let a: number | undefined;\na = 2;\n"
   ],
   "mappings": "IAAI,CAAqB,EAAlB,MAAM,GAAG,SAAS;;AACzB,CAAC,GAAG,CAAC"
 }
\ No newline at end of file
diff --git a/test/samples/ts-undefined-keyword/input.ts b/test/samples/ts-undefined-keyword/input.ts
index 2756c56..b8c21c4 100644
--- a/test/samples/ts-undefined-keyword/input.ts
+++ b/test/samples/ts-undefined-keyword/input.ts
@@ -1,2 +1,2 @@
-let a: number | undefined
-a = 2
\ No newline at end of file
+let a: number | undefined;
+a = 2;
diff --git a/test/samples/with/input.json b/test/samples/with/input.json
index fcb339c..326c95a 100644
--- a/test/samples/with/input.json
+++ b/test/samples/with/input.json
@@ -34,4 +34,4 @@
 		}
 	],
 	"sourceType": "script"
-}
\ No newline at end of file
+}