diff --git a/package.json b/package.json
index bf49a6599f..2b81b03693 100644
--- a/package.json
+++ b/package.json
@@ -216,5 +216,8 @@
 		"websocket": "1.0.26",
 		"ws": "5.2.0",
 		"xev": "2.0.1"
+	},
+	"devDependencies": {
+		"@types/jsdom": "11.0.5"
 	}
 }
diff --git a/src/text/html.ts b/src/text/html.ts
index b55d9b80a7..41adb2e7f7 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 c0396b1fc6..3fb7a3b73d 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, '>')
 		.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 ce25764457..0566ace8b7 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 4821e95fe2..de87aa410b 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 e24231a223..d0eed88965 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 ee57b140b8..cde0c2b224 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 9f9ef51a2b..bcb0bca0ad 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 35563ddc3d..7e0d6f5cf8 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 2ad2788300..a4140458d4 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 cc8cfffdc4..56de561f3f 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 12ee8ecbb8..4bd19ee3fa 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 9f4708f5d6..11b3abc61b 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 1003aff9c3..bbc27b4fd7 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 cfddd9f615..ccfef44591 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/yarn.lock b/yarn.lock
index 8b12a99c95..e4a53091e5 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -277,6 +277,15 @@
   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"
@@ -8221,6 +8230,12 @@ 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"