diff --git a/README.md b/README.md
index cf579266b6..156047304f 100644
--- a/README.md
+++ b/README.md
@@ -97,6 +97,7 @@
   - [`useSessionStorage`](./docs/useSessionStorage.md) — manages a value in `sessionStorage`.
   - [`useThrottle` and `useThrottleFn`](./docs/useThrottle.md) — throttles a function. [![][img-demo]](https://streamich.github.io/react-use/?path=/story/side-effects-usethrottle--demo)
   - [`useTitle`](./docs/useTitle.md) — sets title of the page.
+  - [`usePermission`](./docs/usePermission.md) — query permission from the user depends on the specific API.
     <br/>
     <br/>
 - [**Lifecycles**](./docs/Lifecycles.md)
diff --git a/docs/usePermission.md b/docs/usePermission.md
index 4a6b688e5b..cc793240f2 100644
--- a/docs/usePermission.md
+++ b/docs/usePermission.md
@@ -1,6 +1,6 @@
 # `usePermission`
 
-React UI hook that query permission status from the user depends on the specific AP.
+React side-effect hook that query permission status from the user depends on the specific API.
 
 
 ## Usage
diff --git a/src/__stories__/usePermission.story.tsx b/src/__stories__/usePermission.story.tsx
index 3ff7cf6c9a..77e21ca2f5 100644
--- a/src/__stories__/usePermission.story.tsx
+++ b/src/__stories__/usePermission.story.tsx
@@ -9,6 +9,6 @@ const Demo = () => {
   return <pre>{JSON.stringify(state, null, 2)}</pre>;
 };
 
-storiesOf('UI|usePermission', module)
+storiesOf('Side effects|usePermission', module)
   .add('Docs', () => <ShowDocs md={require('../../docs/usePermission.md')} />)
   .add('Demo', () => <Demo />);
diff --git a/src/usePermission.ts b/src/usePermission.ts
index 37b0261031..2a08d7b1c9 100644
--- a/src/usePermission.ts
+++ b/src/usePermission.ts
@@ -7,13 +7,16 @@ type PermissionDesc =
   | MidiPermissionDescriptor
   | PushPermissionDescriptor;
 
+type State = PermissionState | '';
+
 const noop = () => {};
 
-const usePermission = (permissionDesc: PermissionDesc): string => {
-  const [state, setState] = useState('');
+const usePermission = (permissionDesc: PermissionDesc): State => {
   let mounted = true;
   let permissionStatus: PermissionStatus | null = null;
 
+  const [state, setState] = useState<State>('');
+
   const onChange = () => {
     if (mounted && permissionStatus) {
       setState(permissionStatus.state);