Add TypeScript typings

index.d.ts

@@ -0,0 +1,20 @@
+import {Options as FindUpOptions} from 'find-up';
+import {Options as ReadPkgOptions, PackageMetadata} from 'read-pkg';
+export {PackageMetadata} from 'read-pkg';
+
+export interface Options extends FindUpOptions, ReadPkgOptions {}
+
+export interface PackageInfo {
+	pkg: PackageMetadata;
+	path: string;
+}
+
+/** Returns a `Promise` for the result object. */
+declare function readPkgUp(options?: Options): Promise<PackageInfo>;
+
+declare namespace readPkgUp {
+	/** Returns the result object. */
+	function sync(options?: Options): PackageInfo;
+}
+
+export default readPkgUp;

index.test-d.ts

@@ -0,0 +1,11 @@
+import {expectType} from 'tsd-check';
+import readPkgUp from '.';
+import {PackageMetadata} from '.';
+
+(async () => {
+	expectType<PackageMetadata>(await readPkgUp());
+	expectType<PackageMetadata>(await readPkgUp({ cwd: '.', normalize: false }));
+
+	expectType<PackageMetadata>(readPkgUp.sync());
+	expectType<PackageMetadata>(readPkgUp.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",
@@ -52,6 +53,7 @@
 	},
 	"devDependencies": {
 		"ava": "*",
+		"tsd-check": "^0.2.1",
 		"xo": "*"
 	}
 }