Use localStorage value as react state, sync state across opened tabs


use-local-storage allows you to use value from localStorage as react state. Hook works exactly the same as useState, but also writes the value to local storage:

import { useLocalStorage } from '@mantine/hooks';
// hook will read value from localStorage.getItem('color-scheme')
// if localStorage is not available or value at given key does not exist
// 'dark' will be assigned to value variable
const [value, setValue] = useLocalStorage({ key: 'color-scheme', defaultValue: 'dark' });
// Value is set both to state and localStorage at 'color-scheme'
// You can also use callback like in useState hook to set value
setValue((current) => (current === 'dark' ? 'light' : 'dark'));


Mantine docs website uses this hook to store color scheme information:

import { useLocalStorage } from '@mantine/hooks';
import { ActionIcon, ColorScheme } from '@mantine/core';
import { Sun, MoonStars } from 'tabler-icons-react';
function ColorSchemeToggle() {
const [colorScheme, setColorScheme] = useLocalStorage<ColorScheme>({
key: 'color-scheme',
defaultValue: 'light',
const toggleColorScheme = () =>
setColorScheme((current) => (current === 'dark' ? 'light' : 'dark'));
return (
<ActionIcon onClick={toggleColorScheme}>
{colorScheme === 'dark' ? <Sun /> : <MoonStars />}

Browser tabs synchronization

use-local-storage subscribes to storage event. When state changes in one tab it automatically updates value in all other opened browser tabs. You can test this feature by opening 2 tabs with Mantine docs side by side and changing color scheme (button on the top right or ⌘ + J on mac and Ctrl + J on Windows and Linux).

Serialize/deserialize json

By default, hook will serialize/deserialize data with JSON.stringify/JSON.parse. If you need to store data in local storage that cannot be serialized with JSON.stringify – provide your own serialization handlers:

const [value, setValue] = useLocalStorage({
key: 'color-scheme',
serialize: (value) => {
/* return value serialized to string */
deserialize: (localStorageValue) => {
/* parse localStorage string value and return value */

Usage with superjson

superjson is compatible with JSON.stringify/JSON.parse but works for Date, Map, Set and BigInt:

import superjson from 'superjson';
const [value, setValue] = useLocalStorage({
serialize: superjson.stringify,
deserialize: (str) => (str === undefined ? defaultValue : superjson.parse(str)),



interface UseLocalStorage<T> {
/** Local storage key */
key: string;
/** Default value that will be set if value is not found in local storage */
defaultValue?: T;
/** If set to true, value will be update is useEffect after mount */
getInitialValueInEffect: boolean;
/** Function to serialize value into string to be save in local storage */
serialize?(value: T): string;
/** Function to deserialize string value from local storage to value */
deserialize?(value: string): T;
function useLocalStorage<T = string>({
}: UseLocalStorage<T>): readonly [T, (val: T | ((prevState: T) => T)) => void];

Set value type

You can specify value type same as in useState hook:

const [value, setValue] = useLocalStorage<'dark' | 'light'>({
key: 'color-scheme',
defaultValue: 'light',