diff --git a/.gitignore b/.gitignore
index 86c8bb7..dbab1f4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,6 @@
 /npm-debug.log
 /test.js
 package-lock.json
+
+*.d.ts
+*.d.ts.map
diff --git a/declaration.tsconfig.json b/declaration.tsconfig.json
new file mode 100644
index 0000000..1cde465
--- /dev/null
+++ b/declaration.tsconfig.json
@@ -0,0 +1,12 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "declaration": true,
+    "declarationMap": true,
+    "noEmit": false,
+    "emitDeclarationOnly": true
+  },
+  "exclude": [
+    "**/*.test.js",
+  ]
+}
diff --git a/lib/copy.js b/lib/copy.js
index 1f6d1b2..aab5cb2 100644
--- a/lib/copy.js
+++ b/lib/copy.js
@@ -19,6 +19,14 @@ const removeFile = require('./utils/remove-file')
 // Exports
 // ------------------------------------------------------------------------------
 
+/**
+ * @typedef {{
+    cleaned: string[],
+    copied: string[],
+    options: object
+  }} CopyReport
+ */
+
 /**
  * Copy files asynchronously.
  * @param {string} source The glob pattern of target files.
@@ -32,9 +40,9 @@ const removeFile = require('./utils/remove-file')
  * @param {boolean} [options.preserve=false] The flag to copy file attributes such as timestamps, users, and groups.
  * @param {(function(string):void)[]} [options.transform] The array of the factories of transform streams.
  * @param {boolean} [options.update=false] The flag to not overwrite newer files.
- * @param {string|Array.<string>} [options.ignore] - gitignore string or array of gitignore strings
- * @param {function(Error):void} [callback] The callback function which will go fulfilled after done.
- * @returns {Promise<void>} The promise which will go fulfilled after done.
+ * @param {string[]|string|null|undefined} [options.ignore] - gitignore string or array of gitignore strings
+ * @param {function(Error, CopyReport):void} [callback] The callback function which will go fulfilled after done.
+ * @returns {Promise<CopyReport>} The promise which will go fulfilled after done.
  */
 module.exports = async function copy (source, outputDir, options, callback) {
   /* eslint-disable no-param-reassign */
@@ -81,6 +89,7 @@ module.exports = async function copy (source, outputDir, options, callback) {
     return Promise.resolve()
   })
 
+  /** @type {CopyReport} */
   const report = {
     cleaned,
     copied: copied.filter(r => r), // clean holes,
diff --git a/package.json b/package.json
index 7b84dde..0807a53 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,7 @@
     "node": ">=16"
   },
   "main": "lib/index.js",
+  "types": "./lib/index.d.ts",
   "bin": {
     "cpx": "bin/index.js"
   },
@@ -14,14 +15,18 @@
     "lib"
   ],
   "scripts": {
-    "prepublishOnly": "git push --follow-tags && gh-release -y",
+    "prepublishOnly": "npm run build && git push --follow-tags && gh-release -y",
+    "postpublish": "npm run clean",
     "version": "auto-changelog -p --template keepachangelog auto-changelog --breaking-pattern 'BREAKING CHANGE:' && git add CHANGELOG.md",
     "_mocha": "_mocha \"test/*.js\" --timeout 35000",
-    "clean": "rm -rf .nyc_output coverage test-ws",
+    "clean": "run-p clean:*",
     "coverage": "nyc report -r lcov && opener coverage/lcov-report/index.html",
     "lint": "standard",
     "test": "nyc --require @babel/register npm run -s _mocha",
-    "watch": "npm run -s _mocha -- --require @babel/register --watch --growl"
+    "watch": "npm run -s _mocha -- --require @babel/register --watch --growl",
+    "build": "npm run clean && run-p build:*",
+    "build:declaration": "tsc -p declaration.tsconfig.json",
+    "clean:declarations-lib": "rm -rf $(find {lib,bin} -type f -name '*.d.ts*' ! -name '*-types.d.ts')"
   },
   "dependencies": {
     "debounce": "^1.2.0",
@@ -41,17 +46,21 @@
   "devDependencies": {
     "@babel/core": "^7.5.5",
     "@babel/register": "^7.5.5",
+    "@types/node": "^20.8.9",
+    "@voxpelli/tsconfig": "^9.0.0",
     "auto-changelog": "^2.2.0",
     "babel-preset-power-assert": "^3.0.0",
     "gh-release": "^7.0.2",
     "mocha": "^10.2.0",
+    "npm-run-all2": "^6.1.1",
     "nyc": "15.1.0",
     "opener": "^1.5.1",
     "p-event": "^6.0.0",
     "power-assert": "^1.6.1",
     "shelljs": "^0.8.3",
     "standard": "^17.1.0",
-    "through": "^2.3.8"
+    "through": "^2.3.8",
+    "typescript": "~5.2.2"
   },
   "repository": {
     "type": "git",
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..bf6b7eb
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,13 @@
+{
+  "extends": "@voxpelli/tsconfig/node18.json",
+  "compilerOptions": {
+    "skipLibCheck": true
+  },
+  "include": [
+    "lib/**/*",
+    "bin/**/*"
+  ],
+  "exclude": [
+    "node_modules"
+  ]
+}