Require Node.js 6, add TypeScript definition (#5)

.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

.gitattributes

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

.gitignore

@@ -1 +1,2 @@
 node_modules
+yarn.lock

.npmrc

@@ -0,0 +1 @@
+package-lock=false

.travis.yml

@@ -1,4 +1,5 @@
 language: node_js
 node_js:
+  - '10'
+  - '8'
   - '6'
-  - '4'

index.d.ts

@@ -0,0 +1,21 @@
+export interface Options {
+	/**
+	 * Call the `fn` on the [leading edge of the timeout](https://css-tricks.com/debouncing-throttling-explained-examples/#article-header-id-1). Meaning immediately, instead of waiting for `wait` milliseconds.
+	 *
+	 * @default false
+	 */
+	readonly leading?: boolean;
+}
+
+/**
+ * [Debounce](https://css-tricks.com/debouncing-throttling-explained-examples/) promise-returning & async functions.
+ *
+ * @param fn - Promise-returning/async function to debounce.
+ * @param wait - Milliseconds to wait before calling `fn`.
+ * @returns Returns a function that delays calling `fn` until after `wait` milliseconds have elapsed since the last time it was called.
+ */
+export default function pDebounce<ArgumentsType extends unknown[], ReturnType>(
+	fn: (...arguments: ArgumentsType) => PromiseLike<ReturnType> | ReturnType,
+	wait: number,
+	options?: Options
+): (...arguments: ArgumentsType) => Promise<ReturnType>;

index.js

@@ -1,5 +1,6 @@
 'use strict';
-module.exports = (fn, wait, opts) => {
+
+const pDebounce = (fn, wait, opts) => {
 	if (!Number.isFinite(wait)) {
 		throw new TypeError('Expected `wait` to be a finite number');
 	}
@@ -10,9 +11,8 @@ module.exports = (fn, wait, opts) => {
 	let timer;
 	let resolveList = [];
 
-	return function () {
+	return function (...args) {
 		const ctx = this;
-		const args = arguments;
 
 		return new Promise(resolve => {
 			const runImmediately = opts.leading && !timer;
@@ -40,3 +40,6 @@ module.exports = (fn, wait, opts) => {
 		});
 	};
 };
+
+module.exports = pDebounce;
+module.exports.default = pDebounce;

index.test-d.ts

@@ -0,0 +1,9 @@
+import {expectType} from 'tsd-check';
+import pDebounce from '.';
+
+const expensiveCall = (input: number) => Promise.resolve(input);
+
+expectType<(input: number) => Promise<number>>(pDebounce(expensiveCall, 200));
+expectType<(input: number) => Promise<number>>(
+	pDebounce(expensiveCall, 200, {leading: true})
+);

package.json

@@ -1,52 +1,54 @@
 {
-  "name": "p-debounce",
-  "version": "1.0.0",
-  "description": "Debounce promise-returning & async functions",
-  "license": "MIT",
-  "repository": "sindresorhus/p-debounce",
-  "author": {
-    "name": "Sindre Sorhus",
-    "email": "sindresorhus@gmail.com",
-    "url": "sindresorhus.com"
-  },
-  "engines": {
-    "node": ">=4"
-  },
-  "scripts": {
-    "test": "xo && ava"
-  },
-  "files": [
-    "index.js"
-  ],
-  "keywords": [
-    "promise",
-    "debounce",
-    "debounced",
-    "limit",
-    "limited",
-    "concurrency",
-    "throttle",
-    "throat",
-    "limited",
-    "interval",
-    "rate",
-    "batch",
-    "ratelimit",
-    "task",
-    "queue",
-    "async",
-    "await",
-    "promises",
-    "bluebird"
-  ],
-  "devDependencies": {
-    "ava": "*",
-    "delay": "^1.3.1",
-    "in-range": "^1.0.0",
-    "time-span": "^1.0.0",
-    "xo": "*"
-  },
-  "xo": {
-    "esnext": true
-  }
+	"name": "p-debounce",
+	"version": "1.0.0",
+	"description": "Debounce promise-returning & async functions",
+	"license": "MIT",
+	"repository": "sindresorhus/p-debounce",
+	"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"
+	],
+	"keywords": [
+		"promise",
+		"debounce",
+		"debounced",
+		"limit",
+		"limited",
+		"concurrency",
+		"throttle",
+		"throat",
+		"limited",
+		"interval",
+		"rate",
+		"batch",
+		"ratelimit",
+		"task",
+		"queue",
+		"async",
+		"await",
+		"promises",
+		"bluebird"
+	],
+	"devDependencies": {
+		"ava": "^1.3.1",
+		"delay": "^4.1.0",
+		"in-range": "^1.0.0",
+		"time-span": "^2.0.0",
+		"tsd-check": "^0.3.0",
+		"xo": "^0.24.0"
+	},
+	"xo": {
+		"esnext": true
+	}
 }

readme.md

@@ -38,7 +38,7 @@ Returns a function that delays calling `fn` until after `wait` milliseconds have
 
 Type: `Function`
 
-Promise-returning/async function.
+Promise-returning/async function to debounce.
 
 #### wait
 

test.js

@@ -2,20 +2,20 @@ import test from 'ava';
 import delay from 'delay';
 import inRange from 'in-range';
 import timeSpan from 'time-span';
-import m from './';
+import pDebounce from '.';
 
 const fixture = Symbol('fixture');
 
 test('single call', async t => {
-	const debounced = m(async val => val, 100);
+	const debounced = pDebounce(async val => val, 100);
 	t.is(await debounced(fixture), fixture);
 });
 
 test('multiple calls', async t => {
 	let count = 0;
 	const end = timeSpan();
 
-	const debounced = m(async val => {
+	const debounced = pDebounce(async val => {
 		count++;
 		await delay(50);
 		return val;
@@ -34,7 +34,7 @@ test('multiple calls', async t => {
 test('leading option', async t => {
 	let count = 0;
 
-	const debounced = m(async val => {
+	const debounced = pDebounce(async val => {
 		count++;
 		await delay(50);
 		return val;
@@ -53,7 +53,7 @@ test('leading option', async t => {
 test('leading option - does not call input function after timeout', async t => {
 	let count = 0;
 
-	const debounced = m(async () => {
+	const debounced = pDebounce(async () => {
 		count++;
 	}, 100, {leading: true});