Add TypeScript typings

index.d.ts

@@ -0,0 +1,29 @@
+export interface Options {
+	/**
+	 * Directory to start from.
+	 *
+	 * @default process.cwd()
+	 */
+	cwd?: string;
+
+	/**
+	 * [Normalize](https://github.com/npm/normalize-package-data#what-normalization-currently-entails) the package data.
+	 *
+	 * @default true
+	 */
+	normalize?: boolean;
+}
+
+export interface PackageMetadata {
+	[key: string]: unknown;
+}
+
+/**
+ * Returns a `Promise` for the parsed JSON.
+ */
+export default function (options?: Options): Promise<PackageMetadata>;
+
+/**
+ * Returns the parsed JSON.
+ */
+export function sync(options?: Options): PackageMetadata;

index.test-d.ts

@@ -0,0 +1,8 @@
+import {expectType} from 'tsd-check';
+import readPkg, {PackageMetadata, sync} from '.';
+
+expectType<PackageMetadata>(await readPkg());
+expectType<PackageMetadata>(await readPkg({cwd: '.', normalize: false}));
+
+expectType<PackageMetadata>(sync());
+expectType<PackageMetadata>(sync({cwd: '.', normalize: false}));

package.json

@@ -13,10 +13,11 @@
     "node": ">=6"
   },
   "scripts": {
-    "test": "xo && ava"
+    "test": "xo && ava && tsd-check"
   },
   "files": [
-    "index.js"
+    "index.js",
+    "index.d.ts"
   ],
   "keywords": [
     "json",
@@ -37,6 +38,7 @@
   },
   "devDependencies": {
     "ava": "*",
+    "tsd-check": "^0.2.1",
     "xo": "*"
   }
 }