diff --git a/actions/warn.js b/actions/warn.js
index bc05a1b..b489791 100644
--- a/actions/warn.js
+++ b/actions/warn.js
@@ -1,3 +1,4 @@
+// @ts-check
 'use strict';
 
 const dedent = require('dedent-js');
@@ -26,6 +27,7 @@ module.exports = async ({ admin, amend, reason, userToWarn }) => {
 		{ amend }
 	);
 
+	// @ts-ignore
 	const recentWarns = warns.filter(isNewerThan(date - ms(expireWarnsAfter)));
 
 	const count = {
diff --git a/bot/options.js b/bot/options.js
index 2807efb..bbe3e99 100644
--- a/bot/options.js
+++ b/bot/options.js
@@ -1,5 +1,7 @@
+// @ts-check
 'use strict';
 
+/** @type {import('telegraf/typings/telegram-types').ExtraReplyMessage} */
 const replyOptions = {
 	disable_web_page_preview: true,
 	parse_mode: 'HTML',
diff --git a/handlers/commands/start.js b/handlers/commands/start.js
index ab6391f..f275b74 100644
--- a/handlers/commands/start.js
+++ b/handlers/commands/start.js
@@ -1,4 +1,4 @@
+// @ts-check
 'use strict';
 
-// "clone" the function (https://stackoverflow.com/a/6772648)
-module.exports = require('./help').bind();
+module.exports = require('./help');
diff --git a/handlers/middlewares/index.js b/handlers/middlewares/index.js
index cf45831..5502701 100644
--- a/handlers/middlewares/index.js
+++ b/handlers/middlewares/index.js
@@ -1,7 +1,12 @@
+// @ts-check
 'use strict';
 
 const { Composer } = require('telegraf');
 
+/**
+ * @typedef {import('../../typings/context').ExtendedContext} ExtendedContext
+ * @type {import('telegraf').Composer<ExtendedContext>}
+ */
 const composer = new Composer();
 
 const { deleteAfter } = require('../../utils/tg');
diff --git a/utils/log.js b/utils/log.js
index 1197591..aff94c4 100644
--- a/utils/log.js
+++ b/utils/log.js
@@ -1,21 +1,12 @@
+// @ts-check
 'use strict';
 
 /* eslint-disable no-console */
 
 const { inspect } = require('util');
 
-/**
- * @param {Error} err
- * Logs errors to console
- * @returns {undefined}
- */
 const logError = err => console.error(err);
 
-/**
- * @param {Object} value
- * Echos the value of a value.
- * @returns {undefined}
- */
 const print = value =>
 	console.log(inspect(value, { colors: true, depth: null }));
 
diff --git a/utils/parse.js b/utils/parse.js
index 21c0f6b..9a1862d 100644
--- a/utils/parse.js
+++ b/utils/parse.js
@@ -1,3 +1,4 @@
+// @ts-check
 'use strict';
 
 const XRegExp = require('xregexp');
@@ -21,6 +22,7 @@ const botReply = ({ from, entities = [] }) => {
 
 const flagsRegex = /\s+(?:--?|—)(\w+)(?:=(\S*))?/g;
 
+/** @returns {Generator<[string, string | undefined]>} */
 function *extractFlags(flagS) {
 	for (const [ , name, value ] of flagS.matchAll(flagsRegex)) {
 		yield [ name.toLowerCase(), value ];
diff --git a/utils/tg.js b/utils/tg.js
index 453c814..0776efa 100644
--- a/utils/tg.js
+++ b/utils/tg.js
@@ -1,3 +1,4 @@
+// @ts-check
 'use strict';
 
 const millisecond = require('millisecond');
@@ -40,11 +41,7 @@ const displayUser = user =>
 		? link(user)
 		: html`an user with id <code>${user.id}</code>`;
 
-/**
- * @param {number} ms
- * Deletes messages after (ms) milliseconds
- * @returns {undefined}
- */
+/** @param {number | string | false} ms */
 const deleteAfter = ms => (ctx, next) => {
 	if (ms !== false) {
 		setTimeout(ctx.deleteMessage, millisecond(ms));
@@ -52,6 +49,7 @@ const deleteAfter = ms => (ctx, next) => {
 	next();
 };
 
+/** @param {number | string | false} ms */
 const scheduleDeletion = (ms = 5 * 60 * 1000) => message => {
 	const { chat, message_id } = message;