use-local-storage

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

Usage

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

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'
setValue('light');
// You can also use callback like in useState hook to set value
setValue((current) => (current === 'dark' ? 'light' : 'dark'));

Example

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

import { useLocalStorage } from '@mantine/hooks';
import { ActionIcon, ColorScheme } from '@mantine/core';
import { IconSun, IconMoonStars } from '@tabler/icons';
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' ? <IconSun /> : <IconMoonStars />}
</ActionIcon>
);
}

Remove value

Use removeValue callback to clean localStorage/sessionStorage:

import { useLocalStorage } from '@mantine/hooks';
const [value, setValue, removeValue] = useLocalStorage({
key: 'color-scheme',
defaultValue: 'light',
});

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({
key,
defaultValue,
serialize: superjson.stringify,
deserialize: (str) => (str === undefined ? defaultValue : superjson.parse(str)),
});

use-session-storage

use-session-storage hook works the same way as use-local-storage hook but uses window.sessionStorage instead of window.localStorage:

import { useSessionStorage } from '@mantine/hooks';
const [value, setValue] = useSessionStorage({ key: 'session-key', defaultValue: 'mantine' });

TypeScript

Definition

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>({
key,
defaultValue,
deserialize,
serialize,
getInitialValueInEffect,
}: UseLocalStorage<T>): readonly [
T, // current value
(val: T | ((prevState: T) => T)) => void, // callback to set value in storage
() => void // callback to remove value from storage
];

Set value type

You can specify value type same as in useState hook:

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