Add TypeScript definition, update dependencies (#4)

.gitattributes

@@ -1,2 +1 @@
-* text=auto
-*.js text eol=lf
+* text=auto eol=lf

.travis.yml

@@ -1,3 +1,4 @@
 language: node_js
 node_js:
+  - '10'
   - '8'

index.d.ts

@@ -0,0 +1,7 @@
+/**
+ * Get the email of an npm user.
+ *
+ * @param username - npm username to look up.
+ * @returns A promise for the user's email address.
+ */
+export default function npmEmail(username: string): Promise<string>;

index.js

@@ -1,9 +1,10 @@
 'use strict';
+
 const {URL} = require('url');
 const got = require('got');
 const registryUrl = require('registry-url');
 
-module.exports = async username => {
+const npmEmail = async username => {
 	if (typeof username !== 'string') {
 		throw new TypeError('Username required');
 	}
@@ -13,11 +14,14 @@ module.exports = async username => {
 	try {
 		const {body} = await got(url, {json: true});
 		return body.email;
-	} catch (err) {
-		if (err && err.statusCode === 404) {
+	} catch (error) {
+		if (error && error.statusCode === 404) {
 			throw new Error(`User ${username} doesn't exist`);
 		}
 
-		throw err;
+		throw error;
 	}
 };
+
+module.exports = npmEmail;
+module.exports.default = npmEmail;

index.test-d.ts

@@ -0,0 +1,4 @@
+import {expectType} from 'tsd-check';
+import npmEmail from '.';
+
+expectType<Promise<string>>(npmEmail('sindresorhus'));

package.json

@@ -13,10 +13,11 @@
 		"node": ">=8"
 	},
 	"scripts": {
-		"test": "xo && ava"
+		"test": "xo && ava && tsd-check"
 	},
 	"files": [
-		"index.js"
+		"index.js",
+		"index.d.ts"
 	],
 	"keywords": [
 		"npm",
@@ -29,11 +30,12 @@
 		"get"
 	],
 	"dependencies": {
-		"got": "^8.0.0",
-		"registry-url": "^3.0.0"
+		"got": "^9.6.0",
+		"registry-url": "^4.0.0"
 	},
 	"devDependencies": {
-		"ava": "*",
-		"xo": "*"
+		"ava": "^1.3.1",
+		"tsd-check": "^0.3.0",
+		"xo": "^0.24.0"
 	}
 }

test.js

@@ -1,19 +1,19 @@
 import test from 'ava';
-import m from '.';
+import npmEmail from '.';
 
 test('invalid input', async t => {
-	await t.throws(m(1), 'Username required');
+	await t.throwsAsync(npmEmail(1), 'Username required');
 });
 
 test('unknown username', async t => {
 	const randomName = `asdasfgrgafadsgaf${Math.random().toString().slice(2)}`;
-	await t.throws(m(randomName), `User ${randomName} doesn't exist`);
+	await t.throwsAsync(npmEmail(randomName), `User ${randomName} doesn't exist`);
 });
 
 test('valid username', async t => {
-	t.is(await m('sindresorhus'), 'sindresorhus@gmail.com');
+	t.is(await npmEmail('sindresorhus'), 'sindresorhus@gmail.com');
 });
 
 test('valid username with special character', async t => {
-	t.is(await m(`lukeramsden'`), 'lukeramsden8@gmail.com');
+	t.is(await npmEmail('lukeramsden\''), 'lukeramsden8@gmail.com');
 });