diff --git a/src/client.ts b/src/client.ts
index f200b03d..1ddfd287 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -83,7 +83,7 @@ type Mention = {
 	chanId: number;
 	msgId: number;
 	type: MessageType;
-	time: number;
+	time: Date;
 	text: string;
 	from: UserInMessage;
 };
@@ -312,7 +312,7 @@ class Client {
 			networks: [network.getFilteredClone(this.lastActiveChannel, -1)],
 		});
 
-		if (!(network as NetworkWithIrcFramework).validate(client)) {
+		if (!network.validate(client)) {
 			return;
 		}
 
diff --git a/src/models/msg.ts b/src/models/msg.ts
index f2674ba6..3f2bf84a 100644
--- a/src/models/msg.ts
+++ b/src/models/msg.ts
@@ -7,8 +7,9 @@ export type UserInMessage = Partial<User> & {
 	mode: string;
 };
 
+// TODO: this should be a part of preview in src/plugins/links
 export type MessagePreview = {
-	shown: boolean;
+	shown: boolean | null;
 	link: string;
 	body: string;
 };
@@ -58,7 +59,7 @@ class Msg {
 	// we should probably make Msgs that extend this class and use those
 	// throughout. I'll leave any similar fields below.
 	new_nick!: string;
-	highlight!: boolean;
+	highlight?: boolean;
 	showInActive?: boolean;
 	new_ident!: string;
 	new_host!: string;
@@ -103,7 +104,7 @@ class Msg {
 			self: false,
 		});
 
-		if (this.time.getTime() > 0) {
+		if (this.time?.getTime() > 0) {
 			this.time = new Date(this.time);
 		} else {
 			this.time = new Date();
diff --git a/src/models/network.ts b/src/models/network.ts
index e77f81e5..afbf118d 100644
--- a/src/models/network.ts
+++ b/src/models/network.ts
@@ -177,7 +177,7 @@ class Network {
 		);
 	}
 
-	validate(this: NetworkWithIrcFramework, client: Client) {
+	validate(this: Network, client: Client) {
 		// Remove !, :, @ and whitespace characters from nicknames and usernames
 		const cleanNick = (str: string) => str.replace(/[\x00\s:!@]/g, "_").substring(0, 100);
 
@@ -454,7 +454,7 @@ class Network {
 		this.channels.forEach((channel) => channel.destroy());
 	}
 
-	setNick(this: NetworkWithIrcFramework, nick: string) {
+	setNick(this: Network, nick: string) {
 		this.nick = nick;
 		this.highlightRegex = new RegExp(
 			// Do not match characters and numbers (unless IRC color)
@@ -472,7 +472,10 @@ class Network {
 			this.keepNick = null;
 		}
 
-		this.irc.options.nick = nick;
+		// TODO: setNick is called in validate() before irc exists. Is that a problem?
+		if (this.irc) {
+			this.irc.options.nick = nick;
+		}
 	}
 
 	getFilteredClone(lastActiveChannel: number, lastMessage: number) {
diff --git a/src/plugins/dev-server.ts b/src/plugins/dev-server.ts
index 3344225a..6aabe296 100644
--- a/src/plugins/dev-server.ts
+++ b/src/plugins/dev-server.ts
@@ -13,16 +13,18 @@ export default (app) => {
 		"webpack-hot-middleware/client?path=storage/__webpack_hmr"
 	);
 
+	webpackConfig.plugins.push(new webpack.HotModuleReplacementPlugin());
+
 	const compiler = webpack(webpackConfig);
 
 	app.use(
 		webpackDevMiddleware(compiler, {
 			index: "/",
-			publicPath: webpackConfig.output.publicPath,
+			publicPath: webpackConfig.output?.publicPath,
 		})
 	).use(
 		webpackDevMiddleware(compiler, {
-			path: "/storage/__webpack_hmr",
+			publicPath: "/storage/__webpack_hmr",
 		})
 	);
 };
diff --git a/src/plugins/irc-events/link.ts b/src/plugins/irc-events/link.ts
index 6ceddfb9..a29a5e43 100644
--- a/src/plugins/irc-events/link.ts
+++ b/src/plugins/irc-events/link.ts
@@ -12,7 +12,14 @@ import storage from "../storage";
 import Client, {IrcEventHandler} from "../../client";
 import Chan from "../../models/chan";
 import Msg from "../../models/msg";
-const currentFetchPromises = new Map();
+import {Cheerio} from "cheerio";
+
+type FetchRequest = {
+	data: Record<string, any>;
+	type: string;
+	size: number;
+};
+const currentFetchPromises = new Map<string, Promise<FetchRequest>>();
 const imageTypeRegex = /^image\/.+/;
 const mediaTypeRegex = /^(audio|video)\/.+/;
 
@@ -146,7 +153,7 @@ function parseHtml(preview, res, client: Client) {
 	});
 }
 
-function parseHtmlMedia($: cheerio.Root, preview, client) {
+function parseHtmlMedia($: Cheerio, preview, client: Client) {
 	return new Promise((resolve, reject) => {
 		if (Config.values.disableMediaPreview) {
 			reject();
@@ -417,10 +424,10 @@ function fetch(uri, headers) {
 		);
 	}
 
-	promise = new Promise((resolve, reject) => {
+	promise = new Promise<FetchRequest>((resolve, reject) => {
 		let buffer = Buffer.from("");
 		let contentLength = 0;
-		let contentType;
+		let contentType: string | undefined;
 		let limit = Config.values.prefetchMaxImageSize * 1024;
 
 		try {
@@ -438,14 +445,14 @@ function fetch(uri, headers) {
 					contentLength = parseInt(res.headers["content-length"], 10) || 0;
 					contentType = res.headers["content-type"];
 
-					if (imageTypeRegex.test(contentType)) {
+					if (contentType && imageTypeRegex.test(contentType)) {
 						// response is an image
 						// if Content-Length header reports a size exceeding the prefetch limit, abort fetch
 						// and if file is not to be stored we don't need to download further either
 						if (contentLength > limit || !Config.values.prefetchStorage) {
 							gotStream.destroy();
 						}
-					} else if (mediaTypeRegex.test(contentType)) {
+					} else if (contentType && mediaTypeRegex.test(contentType)) {
 						// We don't need to download the file any further after we received content-type header
 						gotStream.destroy();
 					} else {
diff --git a/src/plugins/irc-events/message.ts b/src/plugins/irc-events/message.ts
index b04aa175..1954bcad 100644
--- a/src/plugins/irc-events/message.ts
+++ b/src/plugins/irc-events/message.ts
@@ -58,7 +58,7 @@ export default <IrcEventHandler>function (irc, network) {
 			data.from_server &&
 			(!data.target ||
 				!network.getChannel(data.target) ||
-				network.getChannel(data.target).type !== ChanType.CHANNEL)
+				network.getChannel(data.target)?.type !== ChanType.CHANNEL)
 		) {
 			chan = network.channels[0];
 			from = chan.getUser(data.nick);
@@ -128,7 +128,7 @@ export default <IrcEventHandler>function (irc, network) {
 		// Self messages in channels are never highlighted
 		// Non-self messages are highlighted as soon as the nick is detected
 		if (!msg.highlight && !msg.self) {
-			msg.highlight = network.highlightRegex.test(data.message);
+			msg.highlight = network.highlightRegex?.test(data.message);
 
 			// If we still don't have a highlight, test against custom highlights if there's any
 			if (!msg.highlight && client.highlightRegex) {
@@ -205,7 +205,7 @@ export default <IrcEventHandler>function (irc, network) {
 				chanId: chan.id,
 				msgId: msg.id,
 				type: msg.type,
-				time: msg.time.getTime(),
+				time: msg.time,
 				text: msg.text,
 				from: msg.from,
 			});
diff --git a/src/plugins/irc-events/mode.ts b/src/plugins/irc-events/mode.ts
index 77c44ef3..1ef2f782 100644
--- a/src/plugins/irc-events/mode.ts
+++ b/src/plugins/irc-events/mode.ts
@@ -4,6 +4,7 @@ import _ from "lodash";
 import {IrcEventHandler} from "../../client";
 
 import Msg, {MessageType} from "../../models/msg";
+import User from "../../models/user";
 
 export default <IrcEventHandler>function (irc, network) {
 	const client = this;
@@ -74,7 +75,7 @@ export default <IrcEventHandler>function (irc, network) {
 			self: data.nick === irc.user.nick,
 		});
 
-		const users = [];
+		const users: User[] = [];
 
 		for (const param of data.raw_params) {
 			if (targetChan.findUser(param)) {
@@ -88,7 +89,7 @@ export default <IrcEventHandler>function (irc, network) {
 
 		targetChan.pushMessage(client, msg);
 
-		let usersUpdated;
+		let usersUpdated = false;
 		const userModeSortPriority = {};
 		const supportsMultiPrefix = network.irc.network.cap.isEnabled("multi-prefix");
 
diff --git a/webpack.config.ts b/webpack.config.ts
index d1ebdd5b..b0f8990a 100644
--- a/webpack.config.ts
+++ b/webpack.config.ts
@@ -158,9 +158,7 @@ export default (env: any, argv: any) => {
 		config.devtool = "eval";
 		config.stats = "errors-only";
 		config.output!.path = path.resolve(__dirname, "test/public");
-		config.entry = {
-			"testclient.js": [path.resolve(__dirname, "test/client/index.js")],
-		};
+		config.entry!["testclient.js"] = [path.resolve(__dirname, "test/client/index.js")];
 
 		// Add the istanbul plugin to babel-loader options
 		for (const rule of config.module!.rules!) {
@@ -194,7 +192,7 @@ export default (env: any, argv: any) => {
 		];
 	}
 
-	if (argv.mode === "production") {
+	if (argv?.mode === "production") {
 		// ...
 	}