Add TypeScript definition (#28)

index.d.ts

@@ -0,0 +1,24 @@
+export type Options = {
+	/**
+	Lorem ipsum.
+
+	@default rainbows
+	*/
+	readonly postfix?: string;
+};
+
+/**
+My awesome module
+
+@param input - Lorem ipsum.
+@returns Lorem ipsum.
+
+@example
+```
+import unicornFun from 'unicorn-fun';
+
+unicornFun('unicorns');
+//=> 'unicorns & rainbows'
+```
+*/
+export default function unicornFun(input: string, options?: Options): string;

package.json

@@ -11,24 +11,28 @@
 		"url": "YOUR WEBSITE"
 	},
 	"type": "module",
-	"exports": "./index.js",
+	"exports": {
+		"types": "./index.d.ts",
+		"default": "./index.js"
+	},
 	"sideEffects": false,
 	"engines": {
 		"node": ">=18"
 	},
 	"scripts": {
-		"test": "xo && ava"
+		"test": "xo && ava && tsc index.d.ts"
 	},
 	"files": [
-		"index.js"
+		"index.js",
+		"index.d.ts"
 	],
 	"keywords": [
 		"unicorn",
 		"fun"
 	],
-	"dependencies": {},
 	"devDependencies": {
 		"ava": "^6.1.3",
+		"typescript": "^5.5.4",
 		"xo": "^0.59.3"
 	}
 }