diff --git a/lib/i18n.ts b/lib/i18n.ts
index e2bc6d3..c595e76 100644
--- a/lib/i18n.ts
+++ b/lib/i18n.ts
@@ -1,16 +1,16 @@
 import { vsprintf } from 'sprintf-js';
 
 interface Options {
-  languages?: string[];
+  languages?: string[] | string;
 }
 
 class i18n {
-  data: object;
+  data: any;
   languages: string[];
 
   constructor(options: Options = {}) {
     this.data = {};
-    this.languages = options.languages || ['default'];
+    this.languages = options.languages as any || ['default'];
 
     if (!Array.isArray(this.languages)) {
       this.languages = [this.languages];
@@ -65,10 +65,10 @@ class i18n {
     return Object.keys(this.data);
   }
 
-  __(lang?: string[]) {
+  __(lang?: string | string[]) {
     const data = this.get(lang);
 
-    return (key: string, ...args) => {
+    return (key?: string, ...args) => {
       if (!key) return '';
 
       const str = data[key] || key;
@@ -77,10 +77,10 @@ class i18n {
     };
   }
 
-  _p(lang?: string[]) {
+  _p(lang?: string | string[]) {
     const data = this.get(lang);
 
-    return (key: string, ...args) => {
+    return (key?: string, ...args) => {
       if (!key) return '';
 
       const number = args.length ? +args[0] : 0;
diff --git a/package.json b/package.json
index 09c2071..c8f7dfd 100644
--- a/package.json
+++ b/package.json
@@ -9,7 +9,7 @@
     "clean": "tsc -b --clean",
     "eslint": "eslint .",
     "pretest": "npm run clean && npm run build",
-    "test": "mocha test/index.js --require ts-node/register",
+    "test": "mocha test/index.ts --require ts-node/register",
     "test-cov": "c8 --reporter=lcovonly npm run test"
   },
   "files": [
@@ -32,6 +32,8 @@
     "sprintf-js": "^1.1.2"
   },
   "devDependencies": {
+    "@types/chai": "^4.3.12",
+    "@types/mocha": "^10.0.6",
     "@types/node": "^18.11.8",
     "@types/sprintf-js": "^1.1.2",
     "c8": "^9.1.0",
diff --git a/test/.eslintrc b/test/.eslintrc
index a938940..7fe2934 100644
--- a/test/.eslintrc
+++ b/test/.eslintrc
@@ -1,7 +1,8 @@
 {
-  "extends": "hexo/test",
+  "extends": "hexo/ts-test",
   "rules": {
     "@typescript-eslint/no-var-requires": 0,
-    "node/no-missing-require": 0
+    "node/no-missing-require": 0,
+    "@typescript-eslint/ban-ts-comment": 0
   }
 }
\ No newline at end of file
diff --git a/test/index.js b/test/index.ts
similarity index 95%
rename from test/index.js
rename to test/index.ts
index 8cfe097..173749f 100644
--- a/test/index.js
+++ b/test/index.ts
@@ -1,10 +1,8 @@
-'use strict';
-
-const should = require('chai').should();
+import chai from 'chai';
+import Ctor from '../lib/i18n';
+const should = chai.should();
 
 describe('i18n', () => {
-  const Ctor = require('../dist/i18n');
-
   const i18n = new Ctor({
     languages: ['zh-TW', 'en']
   });
@@ -78,6 +76,7 @@ describe('i18n', () => {
 
   it('set() - lang must be a string', () => {
     try {
+      // @ts-expect-error
       i18n.set();
     } catch (err) {
       err.should.have.property('message', 'lang must be a string!');
@@ -86,6 +85,7 @@ describe('i18n', () => {
 
   it('set() - data is required', () => {
     try {
+      // @ts-expect-error
       i18n.set('en');
     } catch (err) {
       err.should.have.property('message', 'data is required!');
@@ -131,6 +131,7 @@ describe('i18n', () => {
 
   it('remove() - lang must be a string', () => {
     try {
+      // @ts-expect-error
       i18n.remove();
     } catch (err) {
       err.should.have.property('message', 'lang must be a string!');
diff --git a/tsconfig.json b/tsconfig.json
index 4db8461..dfac976 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -7,7 +7,8 @@
     "declaration": true,
     "esModuleInterop": true,
     "types": [
-      "node"
+      "node",
+      "mocha"
     ]
   },
   "include": [