diff --git a/complex-types.d.ts b/complex-types.d.ts
index 6970171..c4419c0 100644
--- a/complex-types.d.ts
+++ b/complex-types.d.ts
@@ -1,5 +1,15 @@
 import type {Literal} from 'mdast'
 
+// eslint-disable-next-line @typescript-eslint/consistent-type-definitions
+export interface Math extends Literal {
+  type: 'math'
+  meta?: string | null
+}
+
+// eslint-disable-next-line @typescript-eslint/consistent-type-definitions
+export interface InlineMath extends Literal {
+  type: 'inlineMath'
+}
 declare module 'mdast-util-from-markdown' {
   // eslint-disable-next-line @typescript-eslint/consistent-type-definitions
   interface CompileData {
@@ -41,17 +51,6 @@ declare module 'mdast-util-to-markdown' {
   }
 }
 
-// eslint-disable-next-line @typescript-eslint/consistent-type-definitions
-export interface Math extends Literal {
-  type: 'math'
-  meta?: string | null
-}
-
-// eslint-disable-next-line @typescript-eslint/consistent-type-definitions
-export interface InlineMath extends Literal {
-  type: 'inlineMath'
-}
-
 declare module 'mdast' {
   // eslint-disable-next-line @typescript-eslint/consistent-type-definitions
   interface StaticPhrasingContentMap {
diff --git a/index.js b/index.js
index 1769819..c7b4e64 100644
--- a/index.js
+++ b/index.js
@@ -4,8 +4,8 @@
  * @typedef {import('mdast-util-from-markdown').Handle} FromMarkdownHandle
  * @typedef {import('mdast-util-to-markdown').Options} ToMarkdownExtension
  * @typedef {import('mdast-util-to-markdown').Handle} ToMarkdownHandle
- * @typedef {import('./complex-types').Math} Math
- * @typedef {import('./complex-types').InlineMath} InlineMath
+ * @typedef {import('./complex-types.js').Math} Math
+ * @typedef {import('./complex-types.js').InlineMath} InlineMath
  *
  * @typedef ToOptions
  * @property {boolean} [singleDollarTextMath=true]
diff --git a/package.json b/package.json
index 178566d..6d96bc5 100644
--- a/package.json
+++ b/package.json
@@ -55,10 +55,11 @@
     "xo": "^0.53.0"
   },
   "scripts": {
-    "build": "rimraf \"{index,test}.d.ts\" && tsc && type-coverage",
+    "prepack": "npm run build && npm run format",
+    "build": "tsc --build --clean && tsc --build && type-coverage",
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
     "test-api": "node --conditions development test.js",
-    "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov node --conditions development test.js",
+    "test-coverage": "c8 --check-coverage --100 --reporter lcov npm run test-api",
     "test": "npm run build && npm run format && npm run test-coverage"
   },
   "prettier": {
diff --git a/tsconfig.json b/tsconfig.json
index e31adf8..da782de 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,16 +1,17 @@
 {
-  "include": ["*.js"],
+  "include": ["**/*.js", "complex-types.d.ts"],
+  "exclude": ["coverage/", "node_modules/"],
   "compilerOptions": {
-    "target": "ES2020",
-    "lib": ["ES2020"],
-    "module": "ES2020",
-    "moduleResolution": "node",
-    "allowJs": true,
     "checkJs": true,
     "declaration": true,
     "emitDeclarationOnly": true,
-    "allowSyntheticDefaultImports": true,
+    "exactOptionalPropertyTypes": true,
+    "forceConsistentCasingInFileNames": true,
+    "lib": ["es2020"],
+    "module": "node16",
+    "newLine": "lf",
     "skipLibCheck": true,
-    "strict": true
+    "strict": true,
+    "target": "es2020"
   }
 }