diff --git a/gulpfile.ts b/gulpfile.ts
index fa1155878..49a80879d 100644
--- a/gulpfile.ts
+++ b/gulpfile.ts
@@ -8,12 +8,12 @@ import * as gutil from 'gulp-util';
 import * as ts from 'gulp-typescript';
 const sourcemaps = require('gulp-sourcemaps');
 import tslint from 'gulp-tslint';
-import cssnano = require('gulp-cssnano');
+const cssnano = require('gulp-cssnano');
 import * as uglifyComposer from 'gulp-uglify/composer';
 import pug = require('gulp-pug');
 import * as rimraf from 'rimraf';
 import chalk from 'chalk';
-import imagemin = require('gulp-imagemin');
+const imagemin = require('gulp-imagemin');
 import * as rename from 'gulp-rename';
 import * as mocha from 'gulp-mocha';
 import * as replace from 'gulp-replace';
diff --git a/locales/index.ts b/locales/index.ts
index 319d178e0..3b4f76b06 100644
--- a/locales/index.ts
+++ b/locales/index.ts
@@ -5,12 +5,16 @@
 import * as fs from 'fs';
 import * as yaml from 'js-yaml';
 
-const loadLang = lang => yaml.safeLoad(
-	fs.readFileSync(`./locales/${lang}.yml`, 'utf-8'));
+export type LangKey = 'de' | 'en' | 'fr' | 'ja' | 'pl';
+export type LocaleObjectChildren = LocaleObject | string | undefined;
+export type LocaleObject = {[key: string]: LocaleObjectChildren };
+
+const loadLang = (lang: LangKey) => yaml.safeLoad(
+	fs.readFileSync(`./locales/${lang}.yml`, 'utf-8')) as LocaleObject;
 
 const native = loadLang('ja');
 
-const langs = {
+const langs: {[key in LangKey]: LocaleObject} = {
 	'de': loadLang('de'),
 	'en': loadLang('en'),
 	'fr': loadLang('fr'),
@@ -23,4 +27,8 @@ Object.entries(langs).map(([, locale]) => {
 	locale = Object.assign({}, native, locale);
 });
 
+export function isAvailableLanguage(lang: string): lang is LangKey {
+	return lang in langs;
+}
+
 export default langs;
diff --git a/package.json b/package.json
index 9cbbab198..669172338 100644
--- a/package.json
+++ b/package.json
@@ -23,10 +23,10 @@
 		"format": "gulp format"
 	},
 	"dependencies": {
-		"@fortawesome/fontawesome": "1.0.1",
-		"@fortawesome/fontawesome-free-brands": "5.0.2",
-		"@fortawesome/fontawesome-free-regular": "5.0.2",
-		"@fortawesome/fontawesome-free-solid": "5.0.2",
+		"@fortawesome/fontawesome": "1.1.8",
+		"@fortawesome/fontawesome-free-brands": "5.0.13",
+		"@fortawesome/fontawesome-free-regular": "5.0.13",
+		"@fortawesome/fontawesome-free-solid": "5.0.13",
 		"@koa/cors": "2.2.1",
 		"@prezzemolo/rap": "0.1.2",
 		"@prezzemolo/zip": "0.0.3",
@@ -216,5 +216,9 @@
 		"websocket": "1.0.26",
 		"ws": "5.2.0",
 		"xev": "2.0.1"
+	},
+	"devDependencies": {
+		"@types/file-type": "5.2.1",
+		"@types/jsdom": "11.0.5"
 	}
 }
diff --git a/src/build/fa.ts b/src/build/fa.ts
index 111c19ae6..077bb51e6 100644
--- a/src/build/fa.ts
+++ b/src/build/fa.ts
@@ -3,18 +3,18 @@
  */
 
 import * as fontawesome from '@fortawesome/fontawesome';
-import * as regular from '@fortawesome/fontawesome-free-regular';
-import * as solid from '@fortawesome/fontawesome-free-solid';
-import * as brands from '@fortawesome/fontawesome-free-brands';
+import regular from '@fortawesome/fontawesome-free-regular';
+import solid from '@fortawesome/fontawesome-free-solid';
+import brands from '@fortawesome/fontawesome-free-brands';
 
 fontawesome.library.add(regular, solid, brands);
 
 export const pattern = /%fa:(.+?)%/g;
 
-export const replacement = (match, key) => {
+export const replacement = (match: string, key: string) => {
 	const args = key.split(' ');
 	let prefix = 'fas';
-	const classes = [];
+	const classes: string[] = [];
 	let transform = '';
 	let name;
 
@@ -34,12 +34,12 @@ export const replacement = (match, key) => {
 		}
 	});
 
-	const icon = fontawesome.icon({ prefix, iconName: name }, {
-		classes: classes
+	const icon = fontawesome.icon({ prefix, iconName: name } as fontawesome.IconLookup, {
+		classes: classes,
+		transform: fontawesome.parse.transform(transform)
 	});
 
 	if (icon) {
-		icon.transform = fontawesome.parse.transform(transform);
 		return `<i data-fa class="${name}">${icon.html[0]}</i>`;
 	} else {
 		console.warn(`'${name}' not found in fa`);
diff --git a/src/build/i18n.ts b/src/build/i18n.ts
index 35854055d..308ff0da0 100644
--- a/src/build/i18n.ts
+++ b/src/build/i18n.ts
@@ -2,7 +2,7 @@
  * Replace i18n texts
  */
 
-import locale from '../../locales';
+import locale, { isAvailableLanguage, LocaleObject, LocaleObjectChildren } from '../../locales';
 
 export default class Replacer {
 	private lang: string;
@@ -16,19 +16,19 @@ export default class Replacer {
 		this.replacement = this.replacement.bind(this);
 	}
 
-	private get(path: string, key: string) {
-		const texts = locale[this.lang];
-
-		if (texts == null) {
+	private get(path: string, key: string): string {
+		if (!isAvailableLanguage(this.lang)) {
 			console.warn(`lang '${this.lang}' is not supported`);
 			return key; // Fallback
 		}
 
-		let text = texts;
+		const texts = locale[this.lang];
+
+		let text: LocaleObjectChildren = texts;
 
 		if (path) {
 			if (text.hasOwnProperty(path)) {
-				text = text[path];
+				text = text[path] as LocaleObject;
 			} else {
 				console.warn(`path '${path}' not found in '${this.lang}'`);
 				return key; // Fallback
@@ -38,7 +38,7 @@ export default class Replacer {
 		// Check the key existance
 		const error = key.split('.').some(k => {
 			if (text.hasOwnProperty(k)) {
-				text = text[k];
+				text = (text as LocaleObject)[k];
 				return false;
 			} else {
 				return true;
@@ -48,12 +48,15 @@ export default class Replacer {
 		if (error) {
 			console.warn(`key '${key}' not found in '${path}' of '${this.lang}'`);
 			return key; // Fallback
+		} else if (typeof text !== "string") {
+			console.warn(`key '${key}' is not string in '${path}' of '${this.lang}'`);
+			return key; // Fallback
 		} else {
 			return text;
 		}
 	}
 
-	public replacement(match, key) {
+	public replacement(match: string, key: string) {
 		let path = null;
 
 		if (key.indexOf('|') != -1) {
diff --git a/src/client/docs/api/gulpfile.ts b/src/client/docs/api/gulpfile.ts
index 9980ede23..0eb8b8828 100644
--- a/src/client/docs/api/gulpfile.ts
+++ b/src/client/docs/api/gulpfile.ts
@@ -19,9 +19,10 @@ import generateVars from '../vars';
 
 const langs = Object.keys(locales);
 
-const kebab = string => string.replace(/([a-z])([A-Z])/g, '$1-$2').replace(/\s+/g, '-').toLowerCase();
+const kebab = (string: string) => string.replace(/([a-z])([A-Z])/g, '$1-$2').replace(/\s+/g, '-').toLowerCase();
 
-const parseParam = param => {
+// WIP type
+const parseParam = (param: any) => {
 	const id = param.type.match(/^id\((.+?)\)|^id/);
 	const entity = param.type.match(/^entity\((.+?)\)/);
 	const isObject = /^object/.test(param.type);
@@ -57,7 +58,7 @@ const parseParam = param => {
 	return param;
 };
 
-const sortParams = params => {
+const sortParams = (params: Array<{name: string}>) => {
 	params.sort((a, b) => {
 		if (a.name < b.name)
 			return -1;
@@ -68,14 +69,15 @@ const sortParams = params => {
 	return params;
 };
 
-const extractDefs = params => {
-	let defs = [];
+// WIP type
+const extractDefs = (params: any[]) => {
+	let defs: any[] = [];
 
 	params.forEach(param => {
 		if (param.def) {
 			defs.push({
 				name: param.defName,
-				params: sortParams(param.def.map(p => parseParam(p)))
+				params: sortParams(param.def.map((p: any) => parseParam(p)))
 			});
 
 			const childDefs = extractDefs(param.def);
@@ -109,8 +111,10 @@ gulp.task('doc:api:endpoints', async () => {
 					path: ep.endpoint
 				},
 				desc: ep.desc,
+				// @ts-ignore
 				params: sortParams(ep.params.map(p => parseParam(p))),
 				paramDefs: extractDefs(ep.params),
+				// @ts-ignore
 				res: ep.res ? sortParams(ep.res.map(p => parseParam(p))) : null,
 				resDefs: ep.res ? extractDefs(ep.res) : null,
 			};
@@ -155,7 +159,8 @@ gulp.task('doc:api:entities', async () => {
 			const vars = {
 				name: entity.name,
 				desc: entity.desc,
-				props: sortParams(entity.props.map(p => parseParam(p))),
+				// WIP type
+				props: sortParams(entity.props.map((p: any) => parseParam(p))),
 				propDefs: extractDefs(entity.props),
 			};
 			langs.forEach(lang => {
diff --git a/src/client/docs/gulpfile.ts b/src/client/docs/gulpfile.ts
index 56bf6188c..4683a0465 100644
--- a/src/client/docs/gulpfile.ts
+++ b/src/client/docs/gulpfile.ts
@@ -8,8 +8,8 @@ import * as glob from 'glob';
 import * as gulp from 'gulp';
 import * as pug from 'pug';
 import * as mkdirp from 'mkdirp';
-import stylus = require('gulp-stylus');
-import cssnano = require('gulp-cssnano');
+const stylus = require('gulp-stylus');
+const cssnano = require('gulp-cssnano');
 
 import I18nReplacer from '../../build/i18n';
 import fa from '../../build/fa';
diff --git a/src/client/docs/vars.ts b/src/client/docs/vars.ts
index 32b961aaa..93082767e 100644
--- a/src/client/docs/vars.ts
+++ b/src/client/docs/vars.ts
@@ -38,7 +38,7 @@ export default async function(): Promise<{ [key: string]: any }> {
 		vars['docs'][name]['title'][lang] = fs.readFileSync(x, 'utf-8').match(/^h1 (.+?)\r?\n/)[1];
 	});
 
-	vars['kebab'] = string => string.replace(/([a-z])([A-Z])/g, '$1-$2').replace(/\s+/g, '-').toLowerCase();
+	vars['kebab'] = (string: string) => string.replace(/([a-z])([A-Z])/g, '$1-$2').replace(/\s+/g, '-').toLowerCase();
 
 	vars['config'] = config;
 
diff --git a/src/services/drive/add-file.ts b/src/services/drive/add-file.ts
index d7f71e866..4167df066 100644
--- a/src/services/drive/add-file.ts
+++ b/src/services/drive/add-file.ts
@@ -7,7 +7,7 @@ import * as crypto from 'crypto';
 import * as _gm from 'gm';
 import * as debug from 'debug';
 import fileType = require('file-type');
-import prominence = require('prominence');
+const prominence = require('prominence');
 
 import DriveFile, { IMetadata, getDriveFileBucket, IDriveFile } from '../../models/drive-file';
 import DriveFolder from '../../models/drive-folder';
@@ -33,7 +33,7 @@ const writeChunks = (name: string, readable: stream.Readable, type: string, meta
 			readable.pipe(writeStream);
 		}));
 
-const writeThumbnailChunks = (name: string, readable: stream.Readable, originalId) =>
+const writeThumbnailChunks = (name: string, readable: stream.Readable, originalId: mongodb.ObjectID) =>
 	getDriveFileThumbnailBucket()
 		.then(bucket => new Promise((resolve, reject) => {
 			const writeStream = bucket.openUploadStream(name, {
@@ -89,7 +89,7 @@ export default async function(
 	const calcHash = new Promise<string>((res, rej) => {
 		const readable = fs.createReadStream(path);
 		const hash = crypto.createHash('md5');
-		const chunks = [];
+		const chunks: Buffer[] = [];
 		readable
 			.on('error', rej)
 			.pipe(hash)
@@ -201,7 +201,7 @@ export default async function(
 		return driveFolder;
 	};
 
-	const properties = {};
+	const properties: {[key: string]: any} = {};
 
 	let propPromises: Array<Promise<void>> = [];
 
diff --git a/src/services/drive/upload-from-url.ts b/src/services/drive/upload-from-url.ts
index e216ca603..f83d57d41 100644
--- a/src/services/drive/upload-from-url.ts
+++ b/src/services/drive/upload-from-url.ts
@@ -8,10 +8,12 @@ import * as request from 'request';
 import { IDriveFile, validateFileName } from '../../models/drive-file';
 import create from './add-file';
 import config from '../../config';
+import { IUser } from '../../models/user';
+import * as mongodb from "mongodb";
 
 const log = debug('misskey:drive:upload-from-url');
 
-export default async (url: string, user, folderId = null, uri: string = null): Promise<IDriveFile> => {
+export default async (url: string, user: IUser, folderId: mongodb.ObjectID = null, uri: string = null): Promise<IDriveFile> => {
 	log(`REQUESTED: ${url}`);
 
 	let name = URL.parse(url).pathname.split('/').pop();
diff --git a/src/services/note/create.ts b/src/services/note/create.ts
index 98415b897..ef03c4e04 100644
--- a/src/services/note/create.ts
+++ b/src/services/note/create.ts
@@ -33,7 +33,7 @@ class NotificationManager {
 		reason: Reason;
 	}> = [];
 
-	constructor(user, note) {
+	constructor(user: IUser, note: any) {
 		this.user = user;
 		this.note = note;
 	}
@@ -451,7 +451,7 @@ export default async (user: IUser, data: {
 		//		$ne: note._id
 		//	}
 		//});
-		const existRenote = null;
+		const existRenote: INote | null = null;
 		//#endregion
 
 		if (!existRenote) {
diff --git a/src/services/note/reaction/create.ts b/src/services/note/reaction/create.ts
index 123c091c8..5b30bb5e1 100644
--- a/src/services/note/reaction/create.ts
+++ b/src/services/note/reaction/create.ts
@@ -36,7 +36,7 @@ export default async (user: IUser, note: INote, reaction: string) => new Promise
 
 	res();
 
-	const inc = {};
+	const inc: {[key: string]: number} = {};
 	inc[`reactionCounts.${reaction}`] = 1;
 
 	// Increment reactions count
diff --git a/src/text/html.ts b/src/text/html.ts
index b55d9b80a..41adb2e7f 100644
--- a/src/text/html.ts
+++ b/src/text/html.ts
@@ -1,7 +1,8 @@
-import { lib as emojilib } from 'emojilib';
+const { lib: emojilib } = require('emojilib');
 import { JSDOM } from 'jsdom';
 import config from '../config';
 import { INote } from '../models/note';
+import { TextElement } from './parse';
 
 const handlers: {[key: string]: (window: any, token: any, mentionedRemoteUsers: INote["mentionedRemoteUsers"]) => void} = {
 	bold({ document }, { bold }) {
@@ -90,7 +91,7 @@ const handlers: {[key: string]: (window: any, token: any, mentionedRemoteUsers:
 	}
 };
 
-export default (tokens, mentionedRemoteUsers: INote['mentionedRemoteUsers'] = []) => {
+export default (tokens: TextElement[], mentionedRemoteUsers: INote['mentionedRemoteUsers'] = []) => {
 	const { window } = new JSDOM('');
 
 	for (const token of tokens) {
diff --git a/src/text/parse/core/syntax-highlighter.ts b/src/text/parse/core/syntax-highlighter.ts
index c0396b1fc..3fb7a3b73 100644
--- a/src/text/parse/core/syntax-highlighter.ts
+++ b/src/text/parse/core/syntax-highlighter.ts
@@ -1,4 +1,4 @@
-function escape(text) {
+function escape(text: string) {
 	return text
 		.replace(/>/g, '&gt;')
 		.replace(/</g, '&lt;');
@@ -110,7 +110,14 @@ const symbols = [
 	'?'
 ];
 
-const elements = [
+type Token = {
+	html: string
+	next: number
+};
+
+type Element = (code: string, i: number, source: string) => (Token | null);
+
+const elements: Element[] = [
 	// comment
 	code => {
 		if (code.substr(0, 2) != '//') return null;
@@ -305,7 +312,7 @@ export default (source: string, lang?: string) => {
 
 	let i = 0;
 
-	function push(token) {
+	function push(token: Token) {
 		html += token.html;
 		code = code.substr(token.next);
 		i += token.next;
diff --git a/src/text/parse/elements/bold.ts b/src/text/parse/elements/bold.ts
index ce2576445..0566ace8b 100644
--- a/src/text/parse/elements/bold.ts
+++ b/src/text/parse/elements/bold.ts
@@ -2,7 +2,13 @@
  * Bold
  */
 
-module.exports = text => {
+export type TextElementBold = {
+	type: "bold"
+	content: string
+	bold: string
+};
+
+export default function(text: string) {
 	const match = text.match(/^\*\*(.+?)\*\*/);
 	if (!match) return null;
 	const bold = match[0];
@@ -10,5 +16,5 @@ module.exports = text => {
 		type: 'bold',
 		content: bold,
 		bold: bold.substr(2, bold.length - 4)
-	};
-};
+	} as TextElementBold;
+}
diff --git a/src/text/parse/elements/code.ts b/src/text/parse/elements/code.ts
index 4821e95fe..de87aa410 100644
--- a/src/text/parse/elements/code.ts
+++ b/src/text/parse/elements/code.ts
@@ -4,7 +4,14 @@
 
 import genHtml from '../core/syntax-highlighter';
 
-module.exports = text => {
+export type TextElementCode = {
+	type: "code"
+	content: string
+	code: string
+	html: string
+};
+
+export default function(text: string) {
 	const match = text.match(/^```([\s\S]+?)```/);
 	if (!match) return null;
 	const code = match[0];
@@ -13,5 +20,5 @@ module.exports = text => {
 		content: code,
 		code: code.substr(3, code.length - 6).trim(),
 		html: genHtml(code.substr(3, code.length - 6).trim())
-	};
-};
+	} as TextElementCode;
+}
diff --git a/src/text/parse/elements/emoji.ts b/src/text/parse/elements/emoji.ts
index e24231a22..d0eed8896 100644
--- a/src/text/parse/elements/emoji.ts
+++ b/src/text/parse/elements/emoji.ts
@@ -2,7 +2,13 @@
  * Emoji
  */
 
-module.exports = text => {
+export type TextElementEmoji = {
+	type: "emoji"
+	content: string
+	emoji: string
+};
+
+export default function(text: string) {
 	const match = text.match(/^:[a-zA-Z0-9+-_]+:/);
 	if (!match) return null;
 	const emoji = match[0];
@@ -10,5 +16,5 @@ module.exports = text => {
 		type: 'emoji',
 		content: emoji,
 		emoji: emoji.substr(1, emoji.length - 2)
-	};
-};
+	} as TextElementEmoji;
+}
diff --git a/src/text/parse/elements/hashtag.ts b/src/text/parse/elements/hashtag.ts
index ee57b140b..cde0c2b22 100644
--- a/src/text/parse/elements/hashtag.ts
+++ b/src/text/parse/elements/hashtag.ts
@@ -2,7 +2,13 @@
  * Hashtag
  */
 
-module.exports = (text, i) => {
+export type TextElementHashtag = {
+	type: "hashtag"
+	content: string
+	hashtag: string
+};
+
+export default function(text: string, i: number) {
 	if (!(/^\s#[^\s]+/.test(text) || (i == 0 && /^#[^\s]+/.test(text)))) return null;
 	const isHead = text[0] == '#';
 	const hashtag = text.match(/^\s?#[^\s]+/)[0];
@@ -15,5 +21,5 @@ module.exports = (text, i) => {
 		content: isHead ? hashtag : hashtag.substr(1),
 		hashtag: isHead ? hashtag.substr(1) : hashtag.substr(2)
 	});
-	return res;
-};
+	return res as TextElementHashtag[];
+}
diff --git a/src/text/parse/elements/inline-code.ts b/src/text/parse/elements/inline-code.ts
index 9f9ef51a2..bcb0bca0a 100644
--- a/src/text/parse/elements/inline-code.ts
+++ b/src/text/parse/elements/inline-code.ts
@@ -4,7 +4,14 @@
 
 import genHtml from '../core/syntax-highlighter';
 
-module.exports = text => {
+export type TextElementInlineCode = {
+	type: "inline-code"
+	content: string
+	code: string
+	html: string
+};
+
+export default function(text: string) {
 	const match = text.match(/^`(.+?)`/);
 	if (!match) return null;
 	const code = match[0];
@@ -13,5 +20,5 @@ module.exports = text => {
 		content: code,
 		code: code.substr(1, code.length - 2).trim(),
 		html: genHtml(code.substr(1, code.length - 2).trim())
-	};
-};
+	} as TextElementInlineCode;
+}
diff --git a/src/text/parse/elements/link.ts b/src/text/parse/elements/link.ts
index 35563ddc3..7e0d6f5cf 100644
--- a/src/text/parse/elements/link.ts
+++ b/src/text/parse/elements/link.ts
@@ -2,7 +2,15 @@
  * Link
  */
 
-module.exports = text => {
+export type TextElementLink = {
+	type: "link"
+	content: string
+	title: string
+	url: string
+	silent: boolean
+};
+
+export default function(text: string) {
 	const match = text.match(/^\??\[([^\[\]]+?)\]\((https?:\/\/[\w\/:%#@\$&\?!\(\)\[\]~\.=\+\-]+?)\)/);
 	if (!match) return null;
 	const silent = text[0] == '?';
@@ -15,5 +23,5 @@ module.exports = text => {
 		title: title,
 		url: url,
 		silent: silent
-	};
-};
+	} as TextElementLink;
+}
diff --git a/src/text/parse/elements/mention.ts b/src/text/parse/elements/mention.ts
index 2ad278830..a4140458d 100644
--- a/src/text/parse/elements/mention.ts
+++ b/src/text/parse/elements/mention.ts
@@ -3,7 +3,14 @@
  */
 import parseAcct from '../../../acct/parse';
 
-module.exports = text => {
+export type TextElementMention = {
+	type: "mention"
+	content: string
+	username: string
+	host: string
+};
+
+export default function(text: string) {
 	const match = text.match(/^@[a-z0-9_]+(?:@[a-z0-9\.\-]+[a-z0-9])?/i);
 	if (!match) return null;
 	const mention = match[0];
@@ -13,5 +20,5 @@ module.exports = text => {
 		content: mention,
 		username,
 		host
-	};
-};
+	} as TextElementMention;
+}
diff --git a/src/text/parse/elements/quote.ts b/src/text/parse/elements/quote.ts
index cc8cfffdc..56de561f3 100644
--- a/src/text/parse/elements/quote.ts
+++ b/src/text/parse/elements/quote.ts
@@ -2,7 +2,13 @@
  * Quoted text
  */
 
-module.exports = text => {
+export type TextElementQuote = {
+	type: "quote"
+	content: string
+	quote: string
+};
+
+export default function(text: string) {
 	const match = text.match(/^"([\s\S]+?)\n"/);
 	if (!match) return null;
 	const quote = match[0];
@@ -10,5 +16,5 @@ module.exports = text => {
 		type: 'quote',
 		content: quote,
 		quote: quote.substr(1, quote.length - 2).trim(),
-	};
-};
+	} as TextElementQuote;
+}
diff --git a/src/text/parse/elements/search.ts b/src/text/parse/elements/search.ts
index 12ee8ecbb..4bd19ee3f 100644
--- a/src/text/parse/elements/search.ts
+++ b/src/text/parse/elements/search.ts
@@ -2,7 +2,13 @@
  * Search
  */
 
-module.exports = text => {
+export type TextElementSearch = {
+	type: "search"
+	content: string
+	query: string
+};
+
+export default function(text: string) {
 	const match = text.match(/^(.+?) 検索(\n|$)/);
 	if (!match) return null;
 	return {
@@ -10,4 +16,4 @@ module.exports = text => {
 		content: match[0],
 		query: match[1]
 	};
-};
+}
diff --git a/src/text/parse/elements/title.ts b/src/text/parse/elements/title.ts
index 9f4708f5d..11b3abc61 100644
--- a/src/text/parse/elements/title.ts
+++ b/src/text/parse/elements/title.ts
@@ -2,7 +2,13 @@
  * Title
  */
 
-module.exports = text => {
+export type TextElementTitle = {
+	type: "title"
+	content: string
+	title: string
+};
+
+export default function(text: string) {
 	const match = text.match(/^【(.+?)】\n/);
 	if (!match) return null;
 	const title = match[0];
@@ -10,5 +16,5 @@ module.exports = text => {
 		type: 'title',
 		content: title,
 		title: title.substr(1, title.length - 3)
-	};
-};
+	} as TextElementTitle;
+}
diff --git a/src/text/parse/elements/url.ts b/src/text/parse/elements/url.ts
index 1003aff9c..bbc27b4fd 100644
--- a/src/text/parse/elements/url.ts
+++ b/src/text/parse/elements/url.ts
@@ -2,7 +2,13 @@
  * URL
  */
 
-module.exports = text => {
+export type TextElementUrl = {
+	type: "url"
+	content: string
+	url: string
+};
+
+export default function(text: string) {
 	const match = text.match(/^https?:\/\/[\w\/:%#@\$&\?!\(\)\[\]~\.=\+\-]+/);
 	if (!match) return null;
 	const url = match[0];
@@ -10,5 +16,5 @@ module.exports = text => {
 		type: 'url',
 		content: url,
 		url: url
-	};
-};
+	} as TextElementUrl;
+}
diff --git a/src/text/parse/index.ts b/src/text/parse/index.ts
index cfddd9f61..ccfef4459 100644
--- a/src/text/parse/index.ts
+++ b/src/text/parse/index.ts
@@ -2,6 +2,18 @@
  * Misskey Text Analyzer
  */
 
+import { TextElementBold } from "./elements/bold";
+import { TextElementCode } from "./elements/code";
+import { TextElementEmoji } from "./elements/emoji";
+import { TextElementHashtag } from "./elements/hashtag";
+import { TextElementInlineCode } from "./elements/inline-code";
+import { TextElementLink } from "./elements/link";
+import { TextElementMention } from "./elements/mention";
+import { TextElementQuote } from "./elements/quote";
+import { TextElementSearch } from "./elements/search";
+import { TextElementTitle } from "./elements/title";
+import { TextElementUrl } from "./elements/url";
+
 const elements = [
 	require('./elements/bold'),
 	require('./elements/title'),
@@ -14,17 +26,31 @@ const elements = [
 	require('./elements/quote'),
 	require('./elements/emoji'),
 	require('./elements/search')
-];
+].map(element => element.default as TextElementProcessor);
 
-export default (source: string): any[] => {
+export type TextElement = {type: "text", content: string}
+	| TextElementBold
+	| TextElementCode
+	| TextElementEmoji
+	| TextElementHashtag
+	| TextElementInlineCode
+	| TextElementLink
+	| TextElementMention
+	| TextElementQuote
+	| TextElementSearch
+	| TextElementTitle
+	| TextElementUrl;
+export type TextElementProcessor = (text: string, i: number) => TextElement | TextElement[];
+
+export default (source: string): TextElement[] => {
 
 	if (source == '') {
 		return null;
 	}
 
-	const tokens = [];
+	const tokens: TextElement[] = [];
 
-	function push(token) {
+	function push(token: TextElement) {
 		if (token != null) {
 			tokens.push(token);
 			source = source.substr(token.content.length);
@@ -59,9 +85,8 @@ export default (source: string): any[] => {
 	}
 
 	// テキストを纏める
-	tokens[0] = [tokens[0]];
 	return tokens.reduce((a, b) => {
-		if (a[a.length - 1].type == 'text' && b.type == 'text') {
+		if (a.length && a[a.length - 1].type == 'text' && b.type == 'text') {
 			const tail = a.pop();
 			return a.concat({
 				type: 'text',
@@ -70,5 +95,5 @@ export default (source: string): any[] => {
 		} else {
 			return a.concat(b);
 		}
-	});
+	}, [] as TextElement[]);
 };
diff --git a/tsconfig.json b/tsconfig.json
index c407d554e..76221c282 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,7 +2,7 @@
   "compilerOptions": {
     "allowJs": true,
     "noEmitOnError": false,
-    "noImplicitAny": false,
+    "noImplicitAny": true,
     "noImplicitReturns": true,
     "noUnusedParameters": false,
     "noUnusedLocals": true,
diff --git a/yarn.lock b/yarn.lock
index a99e49862..cb6a4a622 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2,21 +2,33 @@
 # yarn lockfile v1
 
 
-"@fortawesome/fontawesome-free-brands@5.0.2":
-  version "5.0.2"
-  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome-free-brands/-/fontawesome-free-brands-5.0.2.tgz#a1cc602eec40a379a3dd8a44c78b31110dd3d3d3"
+"@fortawesome/fontawesome-common-types@^0.1.7":
+  version "0.1.7"
+  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome-common-types/-/fontawesome-common-types-0.1.7.tgz#4336c4b06d0b5608ff1215464b66fcf9f4795284"
 
-"@fortawesome/fontawesome-free-regular@5.0.2":
-  version "5.0.2"
-  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome-free-regular/-/fontawesome-free-regular-5.0.2.tgz#429af86bed14689f87648e6322983c65c782c017"
+"@fortawesome/fontawesome-free-brands@5.0.13":
+  version "5.0.13"
+  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome-free-brands/-/fontawesome-free-brands-5.0.13.tgz#4d15ff4e1e862d5e4a4df3654f8e8acbd47e9c09"
+  dependencies:
+    "@fortawesome/fontawesome-common-types" "^0.1.7"
 
-"@fortawesome/fontawesome-free-solid@5.0.2":
-  version "5.0.2"
-  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome-free-solid/-/fontawesome-free-solid-5.0.2.tgz#090ce2c59dd5ec76983f3da8a43e1ab0321b42d5"
+"@fortawesome/fontawesome-free-regular@5.0.13":
+  version "5.0.13"
+  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome-free-regular/-/fontawesome-free-regular-5.0.13.tgz#eb78c30184e3f456a423a1dcfa0f682f7b50de4a"
+  dependencies:
+    "@fortawesome/fontawesome-common-types" "^0.1.7"
 
-"@fortawesome/fontawesome@1.0.1":
-  version "1.0.1"
-  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome/-/fontawesome-1.0.1.tgz#8ac60e1e7b437889baf9c9d6e3a61ef3b637170d"
+"@fortawesome/fontawesome-free-solid@5.0.13":
+  version "5.0.13"
+  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome-free-solid/-/fontawesome-free-solid-5.0.13.tgz#24b61aaf471a9d34a5364b052d64a516285ba894"
+  dependencies:
+    "@fortawesome/fontawesome-common-types" "^0.1.7"
+
+"@fortawesome/fontawesome@1.1.8":
+  version "1.1.8"
+  resolved "https://registry.yarnpkg.com/@fortawesome/fontawesome/-/fontawesome-1.1.8.tgz#75fe66a60f95508160bb16bd781ad7d89b280f5b"
+  dependencies:
+    "@fortawesome/fontawesome-common-types" "^0.1.7"
 
 "@gulp-sourcemaps/identity-map@1.X":
   version "1.0.1"
@@ -164,6 +176,12 @@
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/@types/fancy-log/-/fancy-log-1.3.0.tgz#a61ab476e5e628cd07a846330df53b85e05c8ce0"
 
+"@types/file-type@5.2.1":
+  version "5.2.1"
+  resolved "https://registry.yarnpkg.com/@types/file-type/-/file-type-5.2.1.tgz#e7af49e08187b6b7598509c5e416669d25fa3461"
+  dependencies:
+    "@types/node" "*"
+
 "@types/form-data@*":
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/@types/form-data/-/form-data-2.2.1.tgz#ee2b3b8eaa11c0938289953606b745b738c54b1e"
@@ -265,6 +283,15 @@
   version "3.11.1"
   resolved "https://registry.yarnpkg.com/@types/js-yaml/-/js-yaml-3.11.1.tgz#ac5bab26be5f9c6f74b6b23420f2cfa5a7a6ba40"
 
+"@types/jsdom@11.0.5":
+  version "11.0.5"
+  resolved "https://registry.yarnpkg.com/@types/jsdom/-/jsdom-11.0.5.tgz#b12fffc73eb3731b218e9665a50f023b6b84b5cb"
+  dependencies:
+    "@types/events" "*"
+    "@types/node" "*"
+    "@types/tough-cookie" "*"
+    parse5 "^3.0.2"
+
 "@types/keygrip@*":
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/@types/keygrip/-/keygrip-1.0.1.tgz#ff540462d2fb4d0a88441ceaf27d287b01c3d878"
@@ -8209,6 +8236,12 @@ parse5@4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/parse5/-/parse5-4.0.0.tgz#6d78656e3da8d78b4ec0b906f7c08ef1dfe3f608"
 
+parse5@^3.0.2:
+  version "3.0.3"
+  resolved "https://registry.yarnpkg.com/parse5/-/parse5-3.0.3.tgz#042f792ffdd36851551cf4e9e066b3874ab45b5c"
+  dependencies:
+    "@types/node" "*"
+
 parseurl@^1.3.0, parseurl@~1.3.2:
   version "1.3.2"
   resolved "https://registry.yarnpkg.com/parseurl/-/parseurl-1.3.2.tgz#fc289d4ed8993119460c156253262cdc8de65bf3"