# Function: useObservable()

> **useObservable**\<`T`, `Args`\>(`obs$`, ...`args`): `Args` *extends* \[\] ? `undefined` \| `T` : `T`

Subscribes the component to an observable and returns its latest value.

Until the observable emits, the hook returns `undefined` or the provided
initial value. The initial value is also used during server rendering.

```tsx
import { useObservable } from '@state-adapt/react';
import { interval } from 'rxjs';

const tick$ = interval(1000);

function Timer() {
  const tick = useObservable(tick$);

  return <p>{tick}</p>;
}
```