Require Node.js 6

.gitattributes

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

.travis.yml

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

package.json

@@ -17,7 +17,7 @@
 		}
 	],
 	"engines": {
-		"node": ">=4"
+		"node": ">=6"
 	},
 	"scripts": {
 		"test": "xo && ava",

test.js

@@ -242,22 +242,22 @@ test('should resolve empty when size is zero', async t => {
 
 	// It should take 1 seconds to resolve all tasks
 	for (let index = 0; index < 100; index++) {
-    queue.add(() => delay(10));
+		queue.add(() => delay(10));
 	}
 
-  queue.onEmpty().then(() => {
-    t.is(queue.size, 0);
-  });
+	queue.onEmpty().then(() => {
+		t.is(queue.size, 0);
+	});
 
-  queue.start();
+	queue.start();
 
 	// Pause at 0.5 second
-  setTimeout(async () => {
-    queue.pause();
-    await delay(10);
-    queue.start();
-  }, 500);
+	setTimeout(async () => {
+		queue.pause();
+		await delay(10);
+		queue.start();
+	}, 500);
 
-  await queue.onIdle();
+	await queue.onIdle();
 });