Require Node.js 8, add TypeScript definition

.travis.yml

@@ -4,6 +4,6 @@ os:
   - windows
 language: node_js
 node_js:
+  - '12'
   - '10'
   - '8'
-  - '6'

index.d.ts

@@ -0,0 +1,21 @@
+declare namespace termSize {
+	interface TermSize {
+		columns: number;
+		rows: number;
+	}
+}
+
+/**
+Reliably get the terminal window size.
+
+@example
+```
+import termSize = require('term-size');
+
+termSize();
+//=> {columns: 143, rows: 24}
+```
+*/
+declare function termSize(): termSize.TermSize;
+
+export = termSize;

index.test-d.ts

@@ -0,0 +1,6 @@
+import {expectType} from 'tsd';
+import termSize = require('.');
+
+const size: termSize.TermSize = termSize();
+expectType<number>(size.columns);
+expectType<number>(size.rows);

package.json

@@ -10,13 +10,14 @@
 		"url": "sindresorhus.com"
 	},
 	"engines": {
-		"node": ">=6"
+		"node": ">=8"
 	},
 	"scripts": {
-		"test": "xo && ava"
+		"test": "xo && ava && tsd"
 	},
 	"files": [
 		"index.js",
+		"index.d.ts",
 		"vendor"
 	],
 	"keywords": [
@@ -37,7 +38,8 @@
 		"execa": "^1.0.0"
 	},
 	"devDependencies": {
-		"ava": "^1.0.1",
-		"xo": "^0.23.0"
+		"ava": "^1.4.1",
+		"tsd": "^0.7.2",
+		"xo": "^0.24.0"
 	}
 }

readme.md

@@ -28,7 +28,7 @@ termSize();
 
 ### termSize()
 
-Returns an `Object` with `columns` and `rows` properties.
+Returns an `object` with `columns` and `rows` properties.
 
 
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