--- title: React useToggler hook type: snippet tags: [hooks,state,callback] author: chalarangelo cover: tram-car-2 dateModified: 2020-11-27T09:41:31+02:00 --- Provides a boolean state variable that can be toggled between its two states. - Use the `useState()` hook to create the `value` state variable and its setter. - Create a function that toggles the value of the `value` state variable and memoize it, using the `useCallback()` hook. - Return the `value` state variable and the memoized toggler function. ```jsx const useToggler = initialState => { const [value, setValue] = React.useState(initialState); const toggleValue = React.useCallback(() => setValue(prev => !prev), []); return [value, toggleValue]; }; ``` ```jsx const Switch = () => { const [val, toggleVal] = useToggler(false); return ; }; ReactDOM.createRoot(document.getElementById('root')).render( ); ```