Add TypeScript definition (#9)

index.d.ts

@@ -0,0 +1,28 @@
+/**
+Simple micro templating.
+
+@param template - Text with placeholders for `data` properties.
+@param data - Data to interpolate into `template`.
+
+@example
+```
+import pupa = require('pupa');
+
+pupa('The mobile number of {name} is {phone.mobile}', {
+	name: 'Sindre',
+	phone: {
+		mobile: '609 24 363'
+	}
+});
+//=> 'The mobile number of Sindre is 609 24 363'
+
+pupa('I like {0} and {1}', ['🦄', '🐮']);
+//=> 'I like 🦄 and 🐮'
+```
+*/
+declare function pupa(
+	template: string,
+	data: unknown[] | {[key: string]: unknown}
+): string;
+
+export = pupa;

index.js

@@ -12,12 +12,12 @@ module.exports = (template, data) => {
 	const regex = /{(.*?)}/g;
 
 	return template.replace(regex, (_, key) => {
-		let ret = data;
+		let result = data;
 
-		for (const prop of key.split('.')) {
-			ret = ret ? ret[prop] : '';
+		for (const property of key.split('.')) {
+			result = result ? result[property] : '';
 		}
 
-		return ret || '';
+		return result || '';
 	});
 };

index.test-d.ts

@@ -0,0 +1,12 @@
+import {expectType} from 'tsd';
+import pupa = require('.');
+
+expectType<string>(
+	pupa('The mobile number of {name} is {phone.mobile}', {
+		name: 'Sindre',
+		phone: {
+			mobile: '609 24 363'
+		}
+	})
+);
+expectType<string>(pupa('I like {0} and {1}', ['🦄', '🐮']));

package.json

@@ -13,10 +13,11 @@
 		"node": ">=6"
 	},
 	"scripts": {
-		"test": "xo && ava"
+		"test": "xo && ava && tsd"
 	},
 	"files": [
-		"index.js"
+		"index.js",
+		"index.d.ts"
 	],
 	"keywords": [
 		"string",
@@ -40,7 +41,8 @@
 		"micro"
 	],
 	"devDependencies": {
-		"ava": "^0.25.0",
-		"xo": "^0.23.0"
+		"ava": "^1.4.1",
+		"tsd": "^0.7.2",
+		"xo": "^0.24.0"
 	}
 }

readme.md

@@ -42,7 +42,7 @@ Text with placeholders for `data` properties.
 
 #### data
 
-Type: `Object` `Array`
+Type: `object | unknown[]`
 
 Data to interpolate into `template`.