Require Node.js 8, add TypeScript definition

.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 @@
+interface UnusedFilename {
+	/**
+	 * Get an unused filename by appending a number if it exists: `file.txt` → `file (1).txt`.
+	 *
+	 * @param filepath - The path to check for filename collision.
+	 * @returns Either the original `filename` or the `filename` appended with a number.
+	 */
+	(filepath: string): Promise<string>;
+
+	/**
+	 * Synchronpusly get an unused filename by appending a number if it exists: `file.txt` → `file (1).txt`.
+	 *
+	 * @param filepath - The path to check for filename collision.
+	 * @returns Either the original `filename` or the `filename` appended with a number.
+	 */
+	sync(filepath: string): string;
+}
+
+declare const unusedFilename: UnusedFilename;
+
+export default unusedFilename;

index.js

@@ -2,17 +2,20 @@
 const pathExists = require('path-exists');
 const modifyFilename = require('modify-filename');
 
-const incrementer = fp => {
+const incrementer = filepath => {
 	let i = 0;
-	return () => modifyFilename(fp, (filename, ext) => `${filename} (${++i})${ext}`);
+	return () => modifyFilename(filepath, (filename, ext) => `${filename} (${++i})${ext}`);
 };
 
-module.exports = fp => {
-	const getFp = incrementer(fp);
-	const find = newFp => pathExists(newFp).then(x => x ? find(getFp()) : newFp);
-	return find(fp);
+const unusedFilename = filepath => {
+	const getFp = incrementer(filepath);
+	const find = newFilepath => pathExists(newFilepath).then(x => x ? find(getFp()) : newFilepath);
+	return find(filepath);
 };
 
+module.exports = unusedFilename;
+module.exports.default = unusedFilename;
+
 module.exports.sync = fp => {
 	const getFp = incrementer(fp);
 	const find = newFp => pathExists.sync(newFp) ? find(getFp()) : newFp;

index.test-d.ts

@@ -0,0 +1,5 @@
+import {expectType} from 'tsd-check';
+import unusedFilename from '.';
+
+expectType<Promise<string>>(unusedFilename('rainbow.txt'));
+expectType<string>(unusedFilename.sync('rainbow.txt'));

package.json

@@ -1,44 +1,46 @@
 {
-  "name": "unused-filename",
-  "version": "1.0.0",
-  "description": "Get an unused filename by appending a number if it exists: `file.txt` → `file (1).txt`",
-  "license": "MIT",
-  "repository": "sindresorhus/unused-filename",
-  "author": {
-    "name": "Sindre Sorhus",
-    "email": "[email protected]",
-    "url": "sindresorhus.com"
-  },
-  "engines": {
-    "node": ">=4"
-  },
-  "scripts": {
-    "test": "xo && ava"
-  },
-  "files": [
-    "index.js"
-  ],
-  "keywords": [
-    "unused",
-    "filename",
-    "filepath",
-    "file",
-    "name",
-    "available",
-    "safe",
-    "unique",
-    "usable",
-    "filesystem",
-    "fs",
-    "exists",
-    "path"
-  ],
-  "dependencies": {
-    "modify-filename": "^1.1.0",
-    "path-exists": "^3.0.0"
-  },
-  "devDependencies": {
-    "ava": "*",
-    "xo": "*"
-  }
+	"name": "unused-filename",
+	"version": "1.0.0",
+	"description": "Get an unused filename by appending a number if it exists: `file.txt` → `file (1).txt`",
+	"license": "MIT",
+	"repository": "sindresorhus/unused-filename",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "[email protected]",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=6"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd-check"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"unused",
+		"filename",
+		"filepath",
+		"file",
+		"name",
+		"available",
+		"safe",
+		"unique",
+		"usable",
+		"filesystem",
+		"fs",
+		"exists",
+		"path"
+	],
+	"dependencies": {
+		"modify-filename": "^1.1.0",
+		"path-exists": "^3.0.0"
+	},
+	"devDependencies": {
+		"ava": "^1.3.1",
+		"tsd-check": "^0.3.0",
+		"xo": "^0.24.0"
+	}
 }

readme.md

@@ -35,16 +35,17 @@ unusedFilename('rainbow.txt').then(filename => {
 
 ### unusedFilename(filepath)
 
-Returns a `Promise<string>`.
+Returns a `Promise<string>` containing either the original `filename` or the `filename` appended with a number.
 
 ### unusedFilename.sync(filepath)
 
-Returns a `string`.
+Returns a `string` containing either the original `filename` or the `filename` appended with a number.
 
 #### filepath
 
 Type: `string`
 
+The path to check for filename collision.
 
 ## Related
 

test.js

@@ -1,14 +1,14 @@
 import test from 'ava';
-import m from '.';
+import unusedFilename from '.';
 
 test('async', async t => {
-	t.is(await m('fixtures/noop.txt'), 'fixtures/noop.txt');
-	t.is(await m('fixtures/unicorn.txt'), 'fixtures/unicorn (1).txt');
-	t.is(await m('fixtures/rainbow.txt'), 'fixtures/rainbow (3).txt');
+	t.is(await unusedFilename('fixtures/noop.txt'), 'fixtures/noop.txt');
+	t.is(await unusedFilename('fixtures/unicorn.txt'), 'fixtures/unicorn (1).txt');
+	t.is(await unusedFilename('fixtures/rainbow.txt'), 'fixtures/rainbow (3).txt');
 });
 
 test('sync', t => {
-	t.is(m.sync('fixtures/noop.txt'), 'fixtures/noop.txt');
-	t.is(m.sync('fixtures/unicorn.txt'), 'fixtures/unicorn (1).txt');
-	t.is(m.sync('fixtures/rainbow.txt'), 'fixtures/rainbow (3).txt');
+	t.is(unusedFilename.sync('fixtures/noop.txt'), 'fixtures/noop.txt');
+	t.is(unusedFilename.sync('fixtures/unicorn.txt'), 'fixtures/unicorn (1).txt');
+	t.is(unusedFilename.sync('fixtures/rainbow.txt'), 'fixtures/rainbow (3).txt');
 });