[breaking] ES2015ify and require Node.js 4

.gitattributes

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

.travis.yml

@@ -1,4 +1,3 @@
-sudo: false
 language: node_js
 node_js:
   - '6'

index.js

@@ -1,5 +1,5 @@
 'use strict';
-module.exports = function (buf) {
+module.exports = buf => {
 	if (!(buf && buf.length > 1)) {
 		return null;
 	}

package.json

@@ -10,7 +10,7 @@
     "url": "sindresorhus.com"
   },
   "engines": {
-    "node": ">=0.10.0"
+    "node": ">=4"
   },
   "scripts": {
     "test": "xo && ava"
@@ -99,5 +99,8 @@
     "ava": "*",
     "read-chunk": "^2.0.0",
     "xo": "*"
+  },
+  "xo": {
+    "esnext": true
   }
 }

readme.md

@@ -17,15 +17,15 @@ $ npm install --save file-type
 ##### Node.js
 
 ```js
-const readChunk = require('read-chunk'); // npm install read-chunk
+const readChunk = require('read-chunk');
 const fileType = require('file-type');
 const buffer = readChunk.sync('unicorn.png', 0, 262);
 
 fileType(buffer);
 //=> {ext: 'png', mime: 'image/png'}
 ```
 
-or from a remote location:
+Or from a remote location:
 
 ```js
 const http = require('http');
@@ -61,11 +61,13 @@ xhr.send();
 
 ### fileType(buffer)
 
-Returns an `Object` (or `null` when no match) with:
+Returns an `Object` with:
 
 - `ext` - one of the [supported file types](#supported-file-types)
 - `mime` - the [MIME type](http://en.wikipedia.org/wiki/Internet_media_type)
 
+Or `null` when no match.
+
 #### buffer
 
 Type: `Buffer` `Uint8Array`

test.js

@@ -6,7 +6,6 @@ import fileType from './';
 function check(ext, name) {
 	const file = path.join(__dirname, 'fixture', `${(name || 'fixture')}.${ext}`);
 	const fileInfo = fileType(readChunk.sync(file, 0, 262)) || {};
-
 	return fileInfo.ext;
 }
 
@@ -83,16 +82,16 @@ const names = {
 	Z: ['fixture.tar']
 };
 
-function testFile(type, name) {
-	test(type, t => {
-		t.is(check(type, name), type);
-	});
+function testFile(t, type, name) {
+	t.is(check(type, name), type);
 }
 
-types.forEach(type => {
-	if ({}.hasOwnProperty.call(names, type)) {
-		names[type].forEach(name => testFile(type, name));
+for (const type of types) {
+	if (Object.prototype.hasOwnProperty.call(names, type)) {
+		for (const name of names[type]) {
+			test(type, testFile, type, name);
+		}
 	} else {
-		testFile(type);
+		test(type, testFile, type);
 	}
-});
+}