diff --git a/src/index.ts b/src/index.ts
index 686a170..d8a284d 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -4,9 +4,13 @@ import ISummary from './isummary';
 import IPlugin from './iplugin';
 import general from './general';
 
+/* plugins */
+import * as amazon from './plugins/amazon';
+import * as wikipedia from './plugins/wikipedia';
+
 const plugins: IPlugin[] = [
-	require('./plugins/amazon'),
-	require('./plugins/wikipedia')
+	amazon,
+	wikipedia
 ];
 
 export default async (url: string): Promise<ISummary> => {
diff --git a/src/plugins/amazon.ts b/src/plugins/amazon.ts
index 14d82e4..b16eab0 100644
--- a/src/plugins/amazon.ts
+++ b/src/plugins/amazon.ts
@@ -4,8 +4,8 @@ const client = require('cheerio-httpcli');
 client.referer = false;
 client.timeout = 10000;
 
-exports.test = (url: URL.Url) =>
-	url.hostname === 'www.amazon.com' ||
+export function test (url: URL.Url) {
+	return url.hostname === 'www.amazon.com' ||
 	url.hostname === 'www.amazon.co.jp' ||
 	url.hostname === 'www.amazon.ca' ||
 	url.hostname === 'www.amazon.com.br' ||
@@ -19,9 +19,9 @@ exports.test = (url: URL.Url) =>
 	url.hostname === 'www.amazon.cn' ||
 	url.hostname === 'www.amazon.in' ||
 	url.hostname === 'www.amazon.au'
-;
+};
 
-exports.summary = async (url: URL.Url) => {
+export async function summary (url: URL.Url) {
 	const res = await client.fetch(url.href);
 	const $: any = res.$;
 
diff --git a/src/plugins/wikipedia.ts b/src/plugins/wikipedia.ts
index 0b76e53..b842c01 100644
--- a/src/plugins/wikipedia.ts
+++ b/src/plugins/wikipedia.ts
@@ -4,28 +4,31 @@ import * as debug from 'debug';
 
 const log = debug('summaly:plugins:wikipedia');
 
-exports.test = (url: URL.Url) =>
-	/\.wikipedia\.org$/.test(url.hostname);
+export function test (url: URL.Url) {
+	return /\.wikipedia\.org$/.test(url.hostname);
+};
 
-exports.summary = (url: URL.Url) => new Promise((res, rej) => {
-	const lang = url.host.split('.')[0];
-	const title = url.pathname.split('/')[2];
-	const endpoint = `https://${lang}.wikipedia.org/w/api.php?format=json&action=query&prop=extracts&exintro=&explaintext=&titles=${encodeURIComponent(title)}`;
+export function summary (url: URL.Url) {
+	return new Promise((res, rej) => {
+		const lang = url.host.split('.')[0];
+		const title = url.pathname.split('/')[2];
+		const endpoint = `https://${lang}.wikipedia.org/w/api.php?format=json&action=query&prop=extracts&exintro=&explaintext=&titles=${encodeURIComponent(title)}`;
 
-	log(`lang is ${lang}`);
-	log(`title is ${title}`);
-	log(`endpoint is ${endpoint}`);
+		log(`lang is ${lang}`);
+		log(`title is ${title}`);
+		log(`endpoint is ${endpoint}`);
 
-	request(endpoint, (err, _, body) => {
-		log(body);
-		body = JSON.parse(body);
-		const info = body.query.pages[Object.keys(body.query.pages)[0]];
-		res({
-			title: info.title,
-			icon: 'https://wikipedia.org/static/favicon/wikipedia.ico',
-			description: info.extract,
-			thumbnail: `https://wikipedia.org/static/images/project-logos/${lang}wiki.png`,
-			sitename: 'Wikipedia'
+		request(endpoint, (err, _, body) => {
+			log(body);
+			body = JSON.parse(body);
+			const info = body.query.pages[Object.keys(body.query.pages)[0]];
+			res({
+				title: info.title,
+				icon: 'https://wikipedia.org/static/favicon/wikipedia.ico',
+				description: info.extract,
+				thumbnail: `https://wikipedia.org/static/images/project-logos/${lang}wiki.png`,
+				sitename: 'Wikipedia'
+			});
 		});
 	});
-});
+};