import { useState, useEffect } from 'react' export function usePersistedState({ key, initialValue, isSessionStorage, }: { key: string initialValue: T isSessionStorage?: boolean }): [T, (x: T | ((prev: T) => T)) => void] { // State to store our value // Pass initial state function to useState so logic is only executed once const [storedValue, setStoredValue] = useState(initialValue) useEffect(() => { if (typeof window === 'undefined') { return } try { // Get from local storage by key const item = window[isSessionStorage ? 'sessionStorage' : 'localStorage'].getItem( key ) // Parse stored json or if none return initialValue if (item) { setStoredValue(JSON.parse(item)) } } catch (error) { // If error also return initialValue console.log(error) } }, [isSessionStorage, key, setStoredValue]) // Return a wrapped version of useState's setter function that ... // ... persists the new value to localStorage. const setValue = (value: T | ((prev: T) => T)): void => { if (typeof window === 'undefined') { return } try { // Allow value to be a function so we have same API as useState const valueToStore = value instanceof Function ? value(storedValue) : value // Save state setStoredValue(valueToStore) // Save to local storage window[isSessionStorage ? 'sessionStorage' : 'localStorage'].setItem( key, JSON.stringify(valueToStore) ) } catch (error) { // A more advanced implementation would handle the error case console.log(error) } } return [storedValue, setValue] }