# `useKey`
React UI sensor hook that executes a `handler` when a keyboard key is used.
## Usage
```jsx
import {useKey} from 'react-use';
const Demo = () => {
const [count, set] = useState(0);
const increment = () => set(count => ++count);
useKey('ArrowUp', increment);
return (
Press arrow up: {count}
);
};
```
Or as render-prop:
```jsx
import UseKey from 'react-use/lib/component/UseKey';
alert('"a" key pressed!')} />
```
## Reference
```js
useKey(filter, handler, options?, deps?)
```
## Examples
```js
useKey('a', () => alert('"a" pressed'));
const predicate = (event) => event.key === 'a'
useKey(predicate, handler, {event: 'keyup'});
```