# `useMountedState` > **NOTE!:** despite having `State` in its name **_this hook does not cause component re-render_**. > This component designed to be used to avoid state updates on unmounted components. Lifecycle hook providing ability to check component's mount state. Returns a function that will return `true` if component mounted and `false` otherwise. ## Usage ```jsx import * as React from 'react'; import {useMountedState} from 'react-use'; const Demo = () => { const isMounted = useMountedState(); React.useEffect(() => { setTimeout(() => { if (isMounted()) { // ... } else { // ... } }, 1000); }); }; ```