2.0.4 • Public • Published


Build Status npm version npm

  1. Version 2.0
    • What's new?
  2. Basic Usage
  3. Supported Browsers
  4. Plugins
  5. Builds
  6. Storages

Version 2.0

Store.js has been around since 2010 (first commit! HN discussion!), and is live on tens of thousands of websites - like!

For many years v1.x provided basic cross-browser persistent storage, and over time more and more people started asking for additional functionality.

Store.js version 2 is a full revamp with pluggable storage (it will automatically fall back to one that works in every scenario by default), pluggable extra functionality (like expirations, default values, common array/object operations, etc), and fully cross-browser automatic testing using

Basic Usage

All you need to know to get started:


store.js exposes a simple API for cross-browser local storage:

// Store current user
store.set('user', { name:'Marcus' })
// Get current user
// Remove current user
// Clear all keys
// Loop over all stored values
store.each(function(value, key) {
    console.log(key, '==', value)


Using npm:

// Example store.js usage with npm
var store = require('store')
store.set('user', { name:'Marcus' })
store.get('user').name == 'Marcus'

Using script tag (first download one of the builds):

<!-- Example store.js usage with script tag -->
<script src="path/to/my/store.legacy.min.js"></script>
var store = require('store')
store.set('user', { name:'Marcus' })
store.get('user').name == 'Marcus'

Supported Browsers

All of them, pretty much :)

To support all browsers (including IE 6, IE 7, Firefox 4, etc.), use require('store') (alias for require('store/dist/store.legacy')) or store.legacy.min.js.

To save some kilobytes but still support all modern browsers, use require('store/dist/store.modern') or store.modern.min.js instead.

List of supported browsers


Plugins provide additional common functionality that some users might need:

List of all Plugins

Using Plugins

With npm:

// Example plugin usage:
var expirePlugin = require('store/plugins/expire')

If you're using script tags, you can either use store.everything.min.js (which has all plugins built-in), or clone this repo to add or modify a build and run make build.

Write your own plugin

A store.js plugin is a function that returns an object that gets added to the store. If any of the plugin functions overrides existing functions, the plugin function can still call the original function using the first argument (super_fn).

// Example plugin that stores a version history of every value
var versionHistoryPlugin = function() {
    var historyStore = this.namespace('history')
    return {
        set: function(super_fn, key, value) {
            var history = historyStore.get(key) || []
            historyStore.set(key, history)
            return super_fn()
        getHistory: function(key) {
            return historyStore.get(key)
store.set('foo', 'bar 1')
store.set('foo', 'bar 2')
store.getHistory('foo') == ['bar 1', 'bar 2']

Let me know if you need more info on writing plugins. For the moment I recommend taking a look at the current plugins. Good example plugins are plugins/defaults, plugins/expire and plugins/events.


Choose which build is right for you!

List of default builds

Make your own Build

If you're using npm you can create your own build:

// Example custom build usage:
var engine = require('store/src/store-engine')
var storages = [
var plugins = [
var store = engine.createStore(storages, plugins)
store.set('foo', 'bar', new Date().getTime() + 3000) // Using expire plugin to expire in 3 seconds


Store.js will pick the best available storage, and automatically falls back to the first available storage that works:

List of all Storages

Storages limits

Each storage has different limits, restrictions and overflow behavior on different browser. For example, Android has has a 4.57M localStorage limit in 4.0, a 2.49M limit in 4.1, and a 4.98M limit in 4.2... Yeah.

To simplify things we provide these recommendations to ensure cross browser behavior:

Storage Targets Recommendations More info
all All browsers Store < 1 million characters (Except Safari Private mode)
all All & Private mode Store < 32 thousand characters (Including Safari Private mode)
localStorage Modern browsers Max 2mb (~1M chars) limits, android
sessionStorage Modern browsers Max 5mb (~2M chars) limits
cookieStorage Safari Private mode Max 4kb (~2K chars) limits
userDataStorage IE5, IE6 & IE7 Max 64kb (~32K chars) limits
globalStorage Firefox 2-5 Max 5mb (~2M chars) limits
memoryStorage All browsers, fallback Does not persist across pages!

Write your own Storage

Chances are you won't ever need another storage. But if you do...

See storages/ for examples. Two good examples are memoryStorage and localStorage.

Basically, you just need an object that looks like this:

// Example custom storage
var storage = {
    name: 'myStorage',
    read: function(key) { ... },
    write: function(key, value) { ... },
    each: function(fn) { ... },
    remove: function(key) { ... },
    clearAll: function() { ... }




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