diff --git a/src/App/AppError.tsx b/src/App/AppError.tsx
index 1583fee..5042e40 100644
--- a/src/App/AppError.tsx
+++ b/src/App/AppError.tsx
@@ -16,11 +16,11 @@ export default class ErrorBoundary extends Component<ErrorProps, ErrorAppState>
     this.state = { hasError: false, error: null, info: null };
   }
 
-  componentDidCatch(error, info) {
+  public componentDidCatch(error, info) {
     this.setState({ hasError: true, error, info });
   }
 
-  render() {
+  public render(): JSX.Element {
     const { hasError, error, info } = this.state;
     const { children } = this.props;
 
diff --git a/src/components/DetailSidebar/DetailSidebar.tsx b/src/components/DetailSidebar/DetailSidebar.tsx
index 66777ea..832ecbd 100644
--- a/src/components/DetailSidebar/DetailSidebar.tsx
+++ b/src/components/DetailSidebar/DetailSidebar.tsx
@@ -16,7 +16,7 @@ import { DetailContext } from '../../pages/Version';
 
 import { TitleListItem, TitleListItemText } from './styles';
 
-const renderLatestDescription = (description, version, isLatest: boolean = true) => {
+const renderLatestDescription = (description, version, isLatest: boolean = true): JSX.Element => {
   return (
     <span>
       <div>{description}</div>
@@ -25,15 +25,15 @@ const renderLatestDescription = (description, version, isLatest: boolean = true)
   );
 };
 
-const renderCopyCLI = () => <Install />;
-const renderMaintainers = () => <Developers type="maintainers" />;
-const renderContributors = () => <Developers type="contributors" />;
-const renderRepository = () => <Repository />;
-const renderAuthor = () => <Author />;
-const renderEngine = () => <Engine />;
-const renderDist = () => <Dist />;
-const renderActionBar = () => <ActionBar />;
-const renderTitle = (packageName, packageVersion, packageMeta) => {
+const renderCopyCLI = (): JSX.Element => <Install />;
+const renderMaintainers = (): JSX.Element => <Developers type="maintainers" />;
+const renderContributors = (): JSX.Element => <Developers type="contributors" />;
+const renderRepository = (): JSX.Element => <Repository />;
+const renderAuthor = (): JSX.Element => <Author />;
+const renderEngine = (): JSX.Element => <Engine />;
+const renderDist = (): JSX.Element => <Dist />;
+const renderActionBar = (): JSX.Element => <ActionBar />;
+const renderTitle = (packageName, packageVersion, packageMeta): JSX.Element => {
   const version = packageVersion ? packageVersion : packageMeta.latest.version;
   const isLatest = typeof packageVersion === 'undefined';
 
@@ -66,7 +66,7 @@ function renderSideBar(packageName, packageVersion, packageMeta): ReactElement<H
   );
 }
 
-const DetailSidebar = () => {
+const DetailSidebar = (): JSX.Element => {
   const { packageName, packageMeta, packageVersion } = React.useContext(DetailContext);
 
   return renderSideBar(packageName, packageVersion, packageMeta);
diff --git a/src/components/Developers/Developers.tsx b/src/components/Developers/Developers.tsx
index 9490139..2fd3e31 100644
--- a/src/components/Developers/Developers.tsx
+++ b/src/components/Developers/Developers.tsx
@@ -22,13 +22,13 @@ const Developers: FC<Props> = ({ type, visibleMax }) => {
     setVisibleDevs(visibleDevs + VISIBLE_MAX);
   };
 
-  const renderDeveloperDetails = ({ name, avatar, email }, packageMeta) => {
+  const renderDeveloperDetails = ({ name, avatar, email }, packageMeta): JSX.Element => {
     const { name: packageName, version } = packageMeta.latest;
 
     return <AvatarTooltip avatar={avatar} email={email} name={name} packageName={packageName} version={version} />;
   };
 
-  const renderDevelopers = (developers, packageMeta) => {
+  const renderDevelopers = (developers, packageMeta): JSX.Element => {
     const listVisibleDevelopers = developers.slice(0, visibleDevs);
 
     return (
diff --git a/src/pages/Version/Version.tsx b/src/pages/Version/Version.tsx
index f707b94..4857521 100644
--- a/src/pages/Version/Version.tsx
+++ b/src/pages/Version/Version.tsx
@@ -19,7 +19,7 @@ export function getRouterPackageName(params): string {
   return packageName;
 }
 
-function fillTitle(text) {
+function fillTitle(text): string {
   return `Verdaccio - ${text}`;
 }
 
diff --git a/src/utils/package.ts b/src/utils/package.ts
index 70365a7..ad5a10b 100644
--- a/src/utils/package.ts
+++ b/src/utils/package.ts
@@ -56,7 +56,7 @@ export function formatDateDistance(lastUpdate): string {
   return distanceInWordsToNow(new Date(lastUpdate));
 }
 
-export function buildScopePackage(scope: string, packageName: string) {
+export function buildScopePackage(scope: string, packageName: string): string {
   return `@${scope}/${packageName}`;
 }