diff --git a/jest/unit/components/__mocks__/api.ts b/jest/unit/components/__mocks__/api.ts
index e4816c0..9f81368 100644
--- a/jest/unit/components/__mocks__/api.ts
+++ b/jest/unit/components/__mocks__/api.ts
@@ -39,8 +39,9 @@ const register = (url, method = 'get', options = {}) => {
  * Bind API methods
  */
 class API {
-  request() {
-    return register.call(null, ...arguments);
+  public request() {
+    const rest = arguments;
+    return register.call(null, ...rest);
   }
 }
 
diff --git a/jest/unit/components/store/logo.ts b/jest/unit/components/store/logo.ts
index ac64387..3a07b37 100644
--- a/jest/unit/components/store/logo.ts
+++ b/jest/unit/components/store/logo.ts
@@ -2,6 +2,6 @@
  * Mock response for logo api
  * @returns {promise}
  */
-export default function() {
+export default function<T>(): Promise<T> {
   return Promise.resolve('http://localhost/-/static/logo.png');
 }
diff --git a/src/App/App.test.tsx b/src/App/App.test.tsx
index 91d302d..f3ef717 100644
--- a/src/App/App.test.tsx
+++ b/src/App/App.test.tsx
@@ -7,7 +7,7 @@ import { generateTokenWithTimeRange } from '../../jest/unit/components/__mocks__
 
 jest.mock('../utils/storage', () => {
   class LocalStorageMock {
-    store: object;
+    private store: object;
     public constructor() {
       this.store = {};
     }
diff --git a/src/App/App.tsx b/src/App/App.tsx
index b75ddc4..24e14b8 100644
--- a/src/App/App.tsx
+++ b/src/App/App.tsx
@@ -19,7 +19,7 @@ export const AppContext = React.createContext<null>(null);
 export const AppContextProvider = AppContext.Provider;
 export const AppContextConsumer = AppContext.Consumer;
 
-export default class App extends Component<any, any> {
+export default class App extends Component {
   public state = {
     error: {},
     // @ts-ignore
diff --git a/src/components/DetailContainer/DetailContainer.tsx b/src/components/DetailContainer/DetailContainer.tsx
index b5945c1..e7e30fa 100644
--- a/src/components/DetailContainer/DetailContainer.tsx
+++ b/src/components/DetailContainer/DetailContainer.tsx
@@ -14,7 +14,7 @@ interface DetailContainerState {
   tabPosition: number;
 }
 
-class DetailContainer extends Component<any, DetailContainerState> {
+class DetailContainer<P> extends Component<P, DetailContainerState> {
   public state = {
     tabPosition: 0,
   };
@@ -29,7 +29,7 @@ class DetailContainer extends Component<any, DetailContainerState> {
     );
   }
 
-  private handleChange = (event: any, tabPosition: number) => {
+  private handleChange = (event: React.ChangeEvent<{}>, tabPosition: number) => {
     event.preventDefault();
     this.setState({ tabPosition });
   };
diff --git a/src/components/RegistryInfoDialog/RegistryInfoDialog.tsx b/src/components/RegistryInfoDialog/RegistryInfoDialog.tsx
index f2c7741..494fc7f 100644
--- a/src/components/RegistryInfoDialog/RegistryInfoDialog.tsx
+++ b/src/components/RegistryInfoDialog/RegistryInfoDialog.tsx
@@ -8,7 +8,7 @@ import { Props } from './types';
 
 const LABEL = 'CLOSE';
 
-const RegistryInfoDialog: React.FC<Props> = ({ open = false, children, onClose }): any => (
+const RegistryInfoDialog: React.FC<Props> = ({ open = false, children, onClose }) => (
   <Dialog id="registryInfo--dialog-container" onClose={onClose} open={open}>
     <Title disableTypography={true}>{'Register Info'}</Title>
     <Content>{children}</Content>
diff --git a/src/components/Search/Search.test.tsx b/src/components/Search/Search.test.tsx
index 27eecdc..795d106 100644
--- a/src/components/Search/Search.test.tsx
+++ b/src/components/Search/Search.test.tsx
@@ -154,7 +154,7 @@ describe('<Search /> component test', () => {
     beforeEach(() => {
       jest.resetModules();
       jest.doMock('lodash/debounce', () => {
-        return function debounceMock(fn, delay) {
+        return function debounceMock(fn) {
           return fn;
         };
       });
diff --git a/src/pages/version/Version.tsx b/src/pages/version/Version.tsx
index a1b4e58..56c7c2c 100644
--- a/src/pages/version/Version.tsx
+++ b/src/pages/version/Version.tsx
@@ -39,7 +39,7 @@ interface StateInterface {
   notFound: boolean;
 }
 
-class VersionPage extends Component<PropsInterface, StateInterface> {
+class VersionPage extends Component<PropsInterface, Partial<StateInterface>> {
   constructor(props) {
     super(props);
 
@@ -81,7 +81,7 @@ class VersionPage extends Component<PropsInterface, StateInterface> {
   public async componentDidUpdate(nextProps, prevState: StateInterface): Promise<void> {
     const { packageName } = this.state;
     if (packageName !== prevState.packageName) {
-      const { readMe, packageMeta } = await callDetailPage(packageName);
+      const { readMe, packageMeta } = (await callDetailPage(packageName)) as Partial<StateInterface>;
       this.setState({
         readMe,
         packageMeta,
@@ -125,7 +125,7 @@ class VersionPage extends Component<PropsInterface, StateInterface> {
     });
 
     try {
-      const { readMe, packageMeta } = await callDetailPage(packageName);
+      const { readMe, packageMeta } = (await callDetailPage(packageName)) as Partial<StateInterface>;
       this.setState({
         readMe,
         packageMeta,
diff --git a/src/utils/api.ts b/src/utils/api.ts
index be94201..4713fc5 100644
--- a/src/utils/api.ts
+++ b/src/utils/api.ts
@@ -25,16 +25,16 @@ function handleResponseType(response: Response): Promise<[boolean, Blob | string
 }
 
 class API {
-  public request(url: string, method = 'GET', options: any = {}): Promise<any> {
+  public request<T>(url: string, method = 'GET', options?: RequestInit): Promise<T> {
     if (!window.VERDACCIO_API_URL) {
       throw new Error('VERDACCIO_API_URL is not defined!');
     }
 
     const token = storage.getItem('token');
-    if (token) {
-      if (!options.headers) options.headers = {};
-
-      options.headers.authorization = `Bearer ${token}`;
+    const headers = new Headers(options && options.headers);
+    if (token && options && options.headers) {
+      headers.set('Authorization', `Bearer ${token}`);
+      options.headers = Object.assign(options.headers, headers);
     }
 
     if (!['http://', 'https://', '//'].some(prefix => url.startsWith(prefix))) {
@@ -42,7 +42,7 @@ class API {
       url = window.VERDACCIO_API_URL + url;
     }
 
-    return new Promise<any>((resolve, reject) => {
+    return new Promise((resolve, reject) => {
       fetch(url, {
         method,
         credentials: 'same-origin',
diff --git a/src/utils/calls.ts b/src/utils/calls.ts
index f44a36d..168fdde 100644
--- a/src/utils/calls.ts
+++ b/src/utils/calls.ts
@@ -2,8 +2,8 @@ import API from './api';
 import { PackageMetaInterface } from 'types/packageMeta';
 
 export interface DetailPage {
-  readMe: string;
-  packageMeta: PackageMetaInterface;
+  readMe: string | {};
+  packageMeta: PackageMetaInterface | {};
 }
 
 export async function callDetailPage(packageName): Promise<DetailPage> {
diff --git a/src/utils/file-size.ts b/src/utils/file-size.ts
index c79ed35..28f20ea 100644
--- a/src/utils/file-size.ts
+++ b/src/utils/file-size.ts
@@ -1,4 +1,4 @@
-/* tslint:disable */
+/* @ts-ignore */
 export default function fileSizeSI(a?: any, b?: any, c?: any, d?: any, e?: any) {
   return ((b = Math), (c = b.log), (d = 1e3), (e = (c(a) / c(d)) | 0), a / b.pow(d, e)).toFixed(2) + ' ' + (e ? 'kMGTPEZY'[--e] + 'B' : 'Bytes');
 }