diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..63d0b74
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,30 @@
+/* (c) 2015 Ari Porad (@ariporad) <http://ariporad.com>. License: ariporad.mit-license.org */
+
+declare type Hook = (code: string, filename: string) => string;
+declare type Matcher = (code: string) => boolean;
+declare type RevertFunction = () => void;
+interface Options {
+  /** A matcher function, will be called with path to a file. Should return truthy if the file should be hooked, falsy otherwise. */
+  matcher?: Matcher;
+  /**
+   * The extensions to hook. Should start with '.' (ex. ['.js']).
+   *
+   * @default ['.js']
+   */
+  exts?: Array<string>;
+  /**
+   * Auto-ignore node_modules. Independent of any matcher.
+   *
+   * @default true
+   */
+  ignoreNodeModules?: boolean;
+}
+/**
+ * Add a require hook.
+ *
+ * @param {Hook} hook - The hook. Accepts the code of the module and the filename. Required.
+ * @param {Options} [opts] - Options
+ * @returns {RevertFunction} revert - Reverts the hooks.
+ */
+export declare function addHook(hook: Hook, opts?: Options): RevertFunction;
+export {};
diff --git a/package.json b/package.json
index cb7a875..97e4713 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,7 @@
   "name": "pirates",
   "description": "Properly hijack require",
   "main": "lib/index.js",
+  "types": "index.d.ts",
   "scripts": {
     "clean": "rimraf lib",
     "build": "babel src -d lib",
@@ -10,7 +11,8 @@
     "prepublish": "yarn run clean && yarn run build"
   },
   "files": [
-    "lib"
+    "lib",
+    "index.d.ts"
   ],
   "repository": {
     "type": "git",
diff --git a/yarn.lock b/yarn.lock
index 6a4ea9e..1501d79 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2081,7 +2081,7 @@ debug@^4.0.0, debug@^4.0.1, debug@^4.1.0, debug@^4.1.1:
   dependencies:
     ms "^2.1.1"
 
-debuglog@*, debuglog@^1.0.1:
+debuglog@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/debuglog/-/debuglog-1.0.1.tgz#aa24ffb9ac3df9a2351837cfb2d279360cd78492"
   integrity sha1-qiT/uaw9+aI1GDfPstJ5NgzXhJI=
@@ -3358,7 +3358,7 @@ import-local@^2.0.0:
     pkg-dir "^3.0.0"
     resolve-cwd "^2.0.0"
 
-imurmurhash@*, imurmurhash@^0.1.4:
+imurmurhash@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/imurmurhash/-/imurmurhash-0.1.4.tgz#9218b9b2b928a238b13dc4fb6b6d576f231453ea"
   integrity sha1-khi5srkoojixPcT7a21XbyMUU+o=
@@ -4103,11 +4103,6 @@ lockfile@^1.0.4:
   dependencies:
     signal-exit "^3.0.2"
 
-lodash._baseindexof@*:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/lodash._baseindexof/-/lodash._baseindexof-3.1.0.tgz#fe52b53a1c6761e42618d654e4a25789ed61822c"
-  integrity sha1-/lK1OhxnYeQmGNZU5KJXie1hgiw=
-
 lodash._baseuniq@~4.6.0:
   version "4.6.0"
   resolved "https://registry.yarnpkg.com/lodash._baseuniq/-/lodash._baseuniq-4.6.0.tgz#0ebb44e456814af7905c6212fa2c9b2d51b841e8"
@@ -4116,33 +4111,11 @@ lodash._baseuniq@~4.6.0:
     lodash._createset "~4.0.0"
     lodash._root "~3.0.0"
 
-lodash._bindcallback@*:
-  version "3.0.1"
-  resolved "https://registry.yarnpkg.com/lodash._bindcallback/-/lodash._bindcallback-3.0.1.tgz#e531c27644cf8b57a99e17ed95b35c748789392e"
-  integrity sha1-5THCdkTPi1epnhftlbNcdIeJOS4=
-
-lodash._cacheindexof@*:
-  version "3.0.2"
-  resolved "https://registry.yarnpkg.com/lodash._cacheindexof/-/lodash._cacheindexof-3.0.2.tgz#3dc69ac82498d2ee5e3ce56091bafd2adc7bde92"
-  integrity sha1-PcaayCSY0u5ePOVgkbr9Ktx73pI=
-
-lodash._createcache@*:
-  version "3.1.2"
-  resolved "https://registry.yarnpkg.com/lodash._createcache/-/lodash._createcache-3.1.2.tgz#56d6a064017625e79ebca6b8018e17440bdcf093"
-  integrity sha1-VtagZAF2JeeevKa4AY4XRAvc8JM=
-  dependencies:
-    lodash._getnative "^3.0.0"
-
 lodash._createset@~4.0.0:
   version "4.0.3"
   resolved "https://registry.yarnpkg.com/lodash._createset/-/lodash._createset-4.0.3.tgz#0f4659fbb09d75194fa9e2b88a6644d363c9fe26"
   integrity sha1-D0ZZ+7CddRlPqeK4imZE02PJ/iY=
 
-lodash._getnative@*, lodash._getnative@^3.0.0:
-  version "3.9.1"
-  resolved "https://registry.yarnpkg.com/lodash._getnative/-/lodash._getnative-3.9.1.tgz#570bc7dede46d61cdcde687d65d3eecbaa3aaff5"
-  integrity sha1-VwvH3t5G1hzc3mh9ZdPuy6o6r/U=
-
 lodash._root@~3.0.0:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/lodash._root/-/lodash._root-3.0.1.tgz#fba1c4524c19ee9a5f8136b4609f017cf4ded692"
@@ -4223,11 +4196,6 @@ lodash.merge@^4.6.1:
   resolved "https://registry.yarnpkg.com/lodash.merge/-/lodash.merge-4.6.1.tgz#adc25d9cb99b9391c59624f379fbba60d7111d54"
   integrity sha512-AOYza4+Hf5z1/0Hztxpm2/xiPZgi/cjMqdnKTUWTBSKchJlxXXuUSxCCl8rJlf4g6yww/j6mA8nC8Hw/EZWxKQ==
 
-lodash.restparam@*:
-  version "3.6.1"
-  resolved "https://registry.yarnpkg.com/lodash.restparam/-/lodash.restparam-3.6.1.tgz#936a4e309ef330a7645ed4145986c85ae5b20805"
-  integrity sha1-k2pOMJ7zMKdkXtQUWYbIWuWyCAU=
-
 lodash.set@^4.3.2:
   version "4.3.2"
   resolved "https://registry.yarnpkg.com/lodash.set/-/lodash.set-4.3.2.tgz#d8757b1da807dde24816b0d6a84bea1a76230b23"
@@ -5864,7 +5832,7 @@ readable-stream@~1.1.10:
     isarray "0.0.1"
     string_decoder "~0.10.x"
 
-readdir-scoped-modules@*, readdir-scoped-modules@^1.0.0:
+readdir-scoped-modules@^1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/readdir-scoped-modules/-/readdir-scoped-modules-1.0.2.tgz#9fafa37d286be5d92cbaebdee030dc9b5f406747"
   integrity sha1-n6+jfShr5dksuuve4DDcm19AZ0c=