Require Node.js 10 (#30)

* Require Node.js 10

* Use util.promisify

.travis.yml

@@ -3,7 +3,6 @@ os:
   - windows
 language: node_js
 node_js:
+  - '14'
   - '12'
   - '10'
-  - '8'
-  - '6'

package.json

@@ -17,7 +17,7 @@
 		}
 	],
 	"engines": {
-		"node": ">=6"
+		"node": ">=10"
 	},
 	"scripts": {
 		"test": "xo && ava"
@@ -44,9 +44,8 @@
 		"is-cwebp-readable": "^3.0.0"
 	},
 	"devDependencies": {
-		"ava": "^0.25.0",
+		"ava": "^3.8.0",
 		"is-webp": "^1.0.0",
-		"pify": "^4.0.0",
-		"xo": "^0.23.0"
+		"xo": "^0.30.0"
 	}
 }

test.js

@@ -1,28 +1,28 @@
-import fs from 'fs';
-import path from 'path';
-import isWebP from 'is-webp';
-import pify from 'pify';
-import test from 'ava';
-import imageminWebp from '.';
+const {promisify} = require('util');
+const fs = require('fs');
+const path = require('path');
+const isWebP = require('is-webp');
+const test = require('ava');
+const imageminWebp = require('.');
 
-const fsP = pify(fs);
+const readFile = promisify(fs.readFile);
 
 test('convert an image into a WebP', async t => {
-	const buf = await fsP.readFile(path.join(__dirname, 'fixtures/test.png'));
+	const buf = await readFile(path.join(__dirname, 'fixtures/test.png'));
 	const data = await imageminWebp()(buf);
 
 	t.true(data.length < buf.length);
 	t.true(isWebP(data));
 });
 
 test('skip optimizing unsupported files', async t => {
-	const buf = await fsP.readFile(path.join(__dirname, 'fixtures/test-unsupported.bmp'));
+	const buf = await readFile(path.join(__dirname, 'fixtures/test-unsupported.bmp'));
 	const data = await imageminWebp()(buf);
 
 	t.deepEqual(data, buf);
 });
 
 test('throw error when an image is corrupt', async t => {
-	const buf = await fsP.readFile(path.join(__dirname, 'fixtures/test-corrupt.webp'));
-	await t.throws(imageminWebp()(buf), /BITSTREAM_ERROR/);
+	const buf = await readFile(path.join(__dirname, 'fixtures/test-corrupt.webp'));
+	await t.throwsAsync(() => imageminWebp()(buf), {message: /BITSTREAM_ERROR/});
 });