diff --git a/.editorconfig b/.editorconfig
index 98a761d..1c6314a 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -7,6 +7,6 @@ charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
 
-[{package.json,*.yml}]
+[*.yml]
 indent_style = space
 indent_size = 2
diff --git a/.gitattributes b/.gitattributes
index 391f0a4..6313b56 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,2 +1 @@
-* text=auto
-*.js text eol=lf
+* text=auto eol=lf
diff --git a/.gitignore b/.gitignore
index 3c3629e..239ecff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 node_modules
+yarn.lock
diff --git a/.npmrc b/.npmrc
new file mode 100644
index 0000000..43c97e7
--- /dev/null
+++ b/.npmrc
@@ -0,0 +1 @@
+package-lock=false
diff --git a/.travis.yml b/.travis.yml
index 97519af..2ae9d62 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,5 @@
 language: node_js
 node_js:
+  - '10'
+  - '8'
   - '6'
-  - '4'
diff --git a/fixture-custom-log.js b/fixture-custom-log.js
index 4d78773..20833f3 100644
--- a/fixture-custom-log.js
+++ b/fixture-custom-log.js
@@ -1,5 +1,5 @@
 'use strict';
-const hardRejection = require('./');
+const hardRejection = require('.');
 
 hardRejection(str => {
 	console.log('custom-log', str);
diff --git a/fixture.js b/fixture.js
index 7e5fe01..fe3a8a7 100644
--- a/fixture.js
+++ b/fixture.js
@@ -1,5 +1,5 @@
 'use strict';
-const hardRejection = require('./');
+const hardRejection = require('.');
 
 hardRejection();
 
diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..7f3d582
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,6 @@
+/**
+Make unhandled promise rejections fail hard right away instead of the default [silent fail](https://gist.github.com/benjamingr/0237932cee84712951a2).
+
+@param log - Custom logging function to print the rejected promise. Receives the error stack. Default: `console.error`.
+*/
+export default function hardRejection(log?: (stack?: string) => void): void;
diff --git a/index.js b/index.js
index ccfe479..163cc91 100644
--- a/index.js
+++ b/index.js
@@ -3,7 +3,7 @@ const util = require('util');
 
 let installed = false;
 
-module.exports = log => {
+const hardRejection = log => {
 	if (installed) {
 		return;
 	}
@@ -17,6 +17,9 @@ module.exports = log => {
 		}
 
 		log(err.stack);
-		process.exit(1); // eslint-disable-line unicorn/no-process-exit
+		process.exit(1);
 	});
 };
+
+module.exports = hardRejection;
+module.exports.default = hardRejection;
diff --git a/index.test-d.ts b/index.test-d.ts
new file mode 100644
index 0000000..33ec556
--- /dev/null
+++ b/index.test-d.ts
@@ -0,0 +1,6 @@
+import {expectType} from 'tsd-check';
+import hardRejection from '.';
+import './register';
+
+expectType<void>(hardRejection());
+expectType<void>(hardRejection(console.log));
diff --git a/license b/license
index 654d0bf..e7af2f7 100644
--- a/license
+++ b/license
@@ -1,21 +1,9 @@
-The MIT License (MIT)
+MIT License
 
 Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
 
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/package.json b/package.json
index b90de6c..023ed60 100644
--- a/package.json
+++ b/package.json
@@ -1,45 +1,47 @@
 {
-  "name": "hard-rejection",
-  "version": "1.0.0",
-  "description": "Make unhandled promise rejections fail hard right away instead of the default silent fail",
-  "license": "MIT",
-  "repository": "sindresorhus/hard-rejection",
-  "author": {
-    "name": "Sindre Sorhus",
-    "email": "sindresorhus@gmail.com",
-    "url": "sindresorhus.com"
-  },
-  "engines": {
-    "node": ">=4"
-  },
-  "scripts": {
-    "test": "xo && ava"
-  },
-  "files": [
-    "index.js",
-    "register.js"
-  ],
-  "keywords": [
-    "promise",
-    "promises",
-    "unhandled",
-    "uncaught",
-    "rejection",
-    "hard",
-    "fail",
-    "catch",
-    "throw",
-    "handler",
-    "exit",
-    "debug",
-    "debugging",
-    "verbose",
-    "immediate",
-    "immediately"
-  ],
-  "devDependencies": {
-    "ava": "*",
-    "execa": "^0.6.0",
-    "xo": "*"
-  }
+	"name": "hard-rejection",
+	"version": "1.0.0",
+	"description": "Make unhandled promise rejections fail hard right away instead of the default silent fail",
+	"license": "MIT",
+	"repository": "sindresorhus/hard-rejection",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=6"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd-check"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts",
+		"register.js"
+	],
+	"keywords": [
+		"promise",
+		"promises",
+		"unhandled",
+		"uncaught",
+		"rejection",
+		"hard",
+		"fail",
+		"catch",
+		"throw",
+		"handler",
+		"exit",
+		"debug",
+		"debugging",
+		"verbose",
+		"immediate",
+		"immediately"
+	],
+	"devDependencies": {
+		"ava": "^1.3.1",
+		"execa": "^1.0.0",
+		"tsd-check": "^0.5.0",
+		"xo": "^0.24.0"
+	}
 }
diff --git a/register.js b/register.js
index 2934812..29f49d7 100644
--- a/register.js
+++ b/register.js
@@ -1,2 +1,2 @@
 'use strict';
-require('./')();
+require('.')();
diff --git a/test.js b/test.js
index 7ab3e9a..21c707b 100644
--- a/test.js
+++ b/test.js
@@ -2,13 +2,13 @@ import test from 'ava';
 import execa from 'execa';
 
 test('main', async t => {
-	const err = await t.throws(execa('node', ['fixture.js']));
+	const err = await t.throwsAsync(execa('node', ['fixture.js']));
 	t.is(err.code, 1);
 	t.regex(err.stderr, /^Error: Unicorn/);
 });
 
 test('custom logging', async t => {
-	const err = await t.throws(execa('node', ['fixture-custom-log.js']));
+	const err = await t.throwsAsync(execa('node', ['fixture-custom-log.js']));
 	t.is(err.code, 1);
 	t.regex(err.stdout, /^custom-log Error: Unicorn/);
 });