use-local-storage-state

use-local-storage-state

React hook with the same API as useState() but persisting the data in local storage

Install

$ npm install use-local-storage-state

Why?

Why this module even exists? There are more than a few libraries to achieve almost the same thing. I created this module in frustration with the big number of non-optimal solutions. Below are the things that this module does right. All bullets are things that some other library isn't doing. Put all together there isn't a single library that solves all these problems:

• Written in TypeScript. useLocalStorageState() returns absolutely the same type as React useState().
• Uses JSON.parse() and JSON.stringify() to support non string values.
• Subscribes to the Window storage event which tracks changes across browser tabs and iframe's.
• Used in a production application which is based on Caret - Markdown Editor for Mac / Windows and is in private beta.
• Supports creating a global hook that can be used in multiple places. See the last example in the Usage section.

Usage

import useLocalStorageState from 'use-local-storage-state'

const [todos, setTodos] = useLocalStorageState('todos', [
    'buy milk',
    'do 50 push-ups'
])

Complete todo list example:

import React, { useState } from 'react'
import useLocalStorageState from 'use-local-storage-state'

export default function Todos() {
    const [query, setQuery] = useState('')
    const [todos, setTodos] = useLocalStorageState('todos', ['buy milk'])

    function onClick() {
        setTodos([...todos, query])
    }

    return (
        <>
            <input value={query} onChange={e => setQuery(e.target.value)} />
            <button onClick={onClick}>Create</button>
            {todos.map(todo => (<div>{todo}</div>))}
        </>
    )
}

Using the same data from the storage in multiple places:

import { createLocalStorageStateHook } from 'use-local-storage-state'

// store.ts
export const useTodos = createLocalStorageStateHook('todos', [
    'buy milk',
    'do 50 push-ups'
])

// Todos.ts
function Todos() {
    const [todos, setTodos] = useTodos()
}

// Popup.ts
function Popup() {
    const [todos, setTodos] = useTodos()
}

API

useLocalStorageState(key, defaultValue?)

Returns the same value that React useState() returns.
Look at Usage section for an example.

key

Type: string

The key that will be used when calling localStorage.setItem(key)and localStorage.getItem(key).
⚠️ Be careful with name conflicts as it is possible to access a property which is already in localStorage that was created from another place in the codebase or in an old version of the application.

defaultValue

Type: any Default: undefined

The initial value of the data. The same as useState(defaultValue) property.

createLocalStorageStateHook(key, defaultValue?)

Returns a hook to be used in multiple places.
Look at Usage section for an example.

key

Type: string

The key that will be used when calling localStorage.setItem(key)and localStorage.getItem(key).
⚠️ Be careful with name conflicts as it is possible to access a property which is already in localStorage that was created from another place in the codebase or in an old version of the application.

defaultValue

Type: any Default: undefined

The initial value of the data. The same as useState(defaultValue) property.