diff --git a/.eslintrc b/.eslintrc
index 8555963a..33e27c40 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -18,9 +18,8 @@
     "@typescript-eslint/no-unsafe-assignment": "off",
     "@typescript-eslint/no-unsafe-member-access": "off",
     "@typescript-eslint/ban-types": "off",
+    "no-nonoctal-decimal-escape": "off",
 
-    "@typescript-eslint/no-unsafe-return": "off",
-    "@typescript-eslint/naming-convention": "off",
-    "no-nonoctal-decimal-escape": "off"
+    "@typescript-eslint/naming-convention": "off"
   }
 }
diff --git a/shlink-web-client.d.ts b/shlink-web-client.d.ts
index 4896a890..58d3c5df 100644
--- a/shlink-web-client.d.ts
+++ b/shlink-web-client.d.ts
@@ -2,7 +2,7 @@ declare module 'event-source-polyfill' {
   declare class EventSourcePolyfill {
     public onmessage?: ({ data }: { data: string }) => void;
     public onerror?: ({ status }: { status: number }) => void;
-    public close: Function;
+    public close: () => void;
     public constructor(hubUrl: URL, options?: any);
   }
 }
diff --git a/src/container/index.ts b/src/container/index.ts
index 58871f19..3cf33996 100644
--- a/src/container/index.ts
+++ b/src/container/index.ts
@@ -20,8 +20,8 @@ type LazyActionMap = Record<string, Function>;
 const bottle = new Bottle();
 const { container } = bottle;
 
-const lazyService = <T extends Function>(container: IContainer, serviceName: string) =>
-  (...args: any[]) => (container[serviceName] as T)(...args);
+const lazyService = <T extends Function, K>(container: IContainer, serviceName: string) =>
+  (...args: any[]) => (container[serviceName] as T)(...args) as K;
 const mapActionService = (map: LazyActionMap, actionName: string): LazyActionMap => ({
   ...map,
   // Wrap actual action service in a function so that it is lazily created the first time it is called
diff --git a/src/mercure/helpers/boundToMercureHub.tsx b/src/mercure/helpers/boundToMercureHub.tsx
index 5b5d5680..82ee96b7 100644
--- a/src/mercure/helpers/boundToMercureHub.tsx
+++ b/src/mercure/helpers/boundToMercureHub.tsx
@@ -6,7 +6,7 @@ import { bindToMercureTopic } from './index';
 
 export interface MercureBoundProps {
   createNewVisits: (createdVisits: CreateVisit[]) => void;
-  loadMercureInfo: Function;
+  loadMercureInfo: () => void;
   mercureInfo: MercureInfo;
 }
 
diff --git a/src/mercure/helpers/index.ts b/src/mercure/helpers/index.ts
index bbd8a8d8..0368c8ee 100644
--- a/src/mercure/helpers/index.ts
+++ b/src/mercure/helpers/index.ts
@@ -1,7 +1,7 @@
 import { EventSourcePolyfill as EventSource } from 'event-source-polyfill';
 import { MercureInfo } from '../reducers/mercureInfo';
 
-export const bindToMercureTopic = <T>(mercureInfo: MercureInfo, topics: string[], onMessage: (message: T) => void, onTokenExpired: Function) => { // eslint-disable-line max-len
+export const bindToMercureTopic = <T>(mercureInfo: MercureInfo, topics: string[], onMessage: (message: T) => void, onTokenExpired: () => void) => { // eslint-disable-line max-len
   const { mercureHubUrl, token, loading, error } = mercureInfo;
 
   if (loading || error || !mercureHubUrl) {
diff --git a/src/servers/services/ServersExporter.ts b/src/servers/services/ServersExporter.ts
index fb610276..114275ae 100644
--- a/src/servers/services/ServersExporter.ts
+++ b/src/servers/services/ServersExporter.ts
@@ -35,7 +35,7 @@ export default class ServersExporter {
   ) {}
 
   public readonly exportServers = async () => {
-    const servers = values(this.storage.get<ServersMap>('servers') || {}).map(dissoc('id'));
+    const servers = values(this.storage.get<ServersMap>('servers') ?? {}).map(dissoc('id'));
 
     try {
       const csv = this.csvjson.toCSV(servers, {
diff --git a/src/utils/services/ColorGenerator.ts b/src/utils/services/ColorGenerator.ts
index 7a9c8abd..46e988df 100644
--- a/src/utils/services/ColorGenerator.ts
+++ b/src/utils/services/ColorGenerator.ts
@@ -11,7 +11,7 @@ export default class ColorGenerator {
   private readonly colors: Record<string, string>;
 
   public constructor(private readonly storage: LocalStorage) {
-    this.colors = this.storage.get<Record<string, string>>('colors') || {};
+    this.colors = this.storage.get<Record<string, string>>('colors') ?? {};
   }
 
   public readonly getColorForKey = (key: string) => {
diff --git a/src/utils/services/LocalStorage.ts b/src/utils/services/LocalStorage.ts
index 20bbb491..914a5a2c 100644
--- a/src/utils/services/LocalStorage.ts
+++ b/src/utils/services/LocalStorage.ts
@@ -4,10 +4,10 @@ const buildPath = (path: string) => `${PREFIX}.${path}`;
 export default class LocalStorage {
   public constructor(private readonly localStorage: Storage) {}
 
-  public readonly get = <T>(key: string): T => {
+  public readonly get = <T>(key: string): T | undefined => {
     const item = this.localStorage.getItem(buildPath(key));
 
-    return item ? JSON.parse(item) : undefined;
+    return item ? JSON.parse(item) as T : undefined;
   };
 
   public readonly set = (key: string, value: any) => this.localStorage.setItem(buildPath(key), JSON.stringify(value));
diff --git a/test/servers/services/ServersImporter.test.ts b/test/servers/services/ServersImporter.test.ts
index f6749ca6..60e5dfc4 100644
--- a/test/servers/services/ServersImporter.test.ts
+++ b/test/servers/services/ServersImporter.test.ts
@@ -10,7 +10,9 @@ describe('ServersImporter', () => {
   const readAsText = jest.fn();
   const fileReaderMock = Mock.of<FileReader>({
     readAsText,
-    addEventListener: (_eventName: string, listener: Function) => listener({ target: { result: '' } }),
+    addEventListener: (_eventName: string, listener: (e: ProgressEvent<FileReader>) => void) => listener(
+      Mock.of<ProgressEvent<FileReader>>({ target: { result: '' } }),
+    ),
   });
   const importer = new ServersImporter(csvjsonMock, () => fileReaderMock);