Add TypeScript definition (#2)

.gitattributes

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

.travis.yml

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

index.d.ts

@@ -0,0 +1,6 @@
+/**
+ * Capitalize every word in a string: `unicorn cake` → `Unicorn Cake`.
+ *
+ * @param input - The string to titleize.
+ */
+export default function titleize(input: string): string;

index.js

@@ -1,8 +1,11 @@
 'use strict';
-module.exports = input => {
+const titleize = input => {
 	if (typeof input !== 'string') {
 		throw new TypeError('Expected a string');
 	}
 
 	return input.toLowerCase().replace(/(?:^|\s|-)\S/g, x => x.toUpperCase());
 };
+
+module.exports = titleize;
+module.exports.default = titleize;

index.test-d.ts

@@ -0,0 +1,4 @@
+import {expectType} from 'tsd-check';
+import titleize from '.';
+
+expectType<string>(titleize('foo bar'));

package.json

@@ -13,10 +13,11 @@
 		"node": ">=6"
 	},
 	"scripts": {
-		"test": "xo && ava"
+		"test": "xo && ava && tsd-check"
 	},
 	"files": [
-		"index.js"
+		"index.js",
+		"index.d.ts"
 	],
 	"keywords": [
 		"titleize",
@@ -31,7 +32,8 @@
 		"convert"
 	],
 	"devDependencies": {
-		"ava": "*",
-		"xo": "*"
+		"ava": "^1.2.1",
+		"tsd-check": "^0.3.0",
+		"xo": "^0.24.0"
 	}
 }

test.js

@@ -1,11 +1,11 @@
 import test from 'ava';
-import m from '.';
+import titleize from '.';
 
 test('main', t => {
-	t.is(m(''), '');
-	t.is(m('unicorns and rainbows'), 'Unicorns And Rainbows');
-	t.is(m('UNICORNS AND RAINBOWS'), 'Unicorns And Rainbows');
-	t.is(m('unicorns-and-rainbows'), 'Unicorns-And-Rainbows');
-	t.is(m('UNICORNS-AND-RAINBOWS'), 'Unicorns-And-Rainbows');
-	t.is(m('unicorns   and rainbows'), 'Unicorns   And Rainbows');
+	t.is(titleize(''), '');
+	t.is(titleize('unicorns and rainbows'), 'Unicorns And Rainbows');
+	t.is(titleize('UNICORNS AND RAINBOWS'), 'Unicorns And Rainbows');
+	t.is(titleize('unicorns-and-rainbows'), 'Unicorns-And-Rainbows');
+	t.is(titleize('UNICORNS-AND-RAINBOWS'), 'Unicorns-And-Rainbows');
+	t.is(titleize('unicorns   and rainbows'), 'Unicorns   And Rainbows');
 });