store2

What is store2?

The store2 npm package is a simple, lightweight JavaScript library for cross-browser local storage with a simple but powerful API. It provides an easy way to store, retrieve, and manage data in the browser's local storage and session storage, with additional features such as namespacing and cross-tab communication.

What are store2's main functionalities?

Basic storage operations

Perform basic local storage operations such as setting, getting, removing, and clearing all items.

{"set": "store.set('user', {name: 'Marcus'})", "get": "store.get('user')", "remove": "store.remove('user')", "clearAll": "store.clearAll()"}

Namespacing

Create a namespace to group related data and perform operations within that namespace.

{"createNamespace": "var userStore = store.namespace('user')", "namespaceSet": "userStore.set('info', {name: 'Marcus'})", "namespaceGet": "userStore.get('info')"}

Cross-tab communication

Enable cross-tab communication by setting a flag that will trigger the storage event listener when data is changed.

{"setListen": "store.set('user', {name: 'Marcus'}, true)", "onStorage": "window.addEventListener('storage', function(e) { console.log('storage changed', e.key); })"}

Additional storage methods

Use additional methods to retrieve all stored items, iterate over them, or perform a transactional operation on a stored object.

{"getAll": "store.getAll()", "each": "store.each(function(value, key) { console.log(key, '==', value); })", "transact": "store.transact('user', function(user) { user.visits = (user.visits || 0) + 1; })"}

Other packages similar to store2

js-cookie

js-cookie is a simple, lightweight JavaScript API for handling browser cookies. It allows you to create, read, and delete cookies with ease. While store2 focuses on local and session storage, js-cookie is specifically designed for cookie storage, which can be useful for storing data that needs to be sent to the server on each request.

redux-persist

redux-persist is a library allowing to save a Redux store state in a persistent storage and rehydrate it on app start. It is more specialized than store2 as it is designed to work with Redux applications, providing a seamless way to persist and rehydrate the Redux state tree.

README

A feature-filled and friendly way to take advantage of localStorage and sessionStorage (JSON, namespacing, extensions, etc).

Download: store.min.js or store.js
NPM: npm install store2 (store was taken)
Bower: bower install store

Documentation

The main store function can handle set, get, setAll, getAll and clear actions directly. Respectively, these are called like so:

store(key, data);
store(key);
store({key: data, key2: data2});
store();
store(false);

There are also more explicit and versatile functions available:

store.set(key, data[, overwrite]); // === store(key, data);
store.setAll(data[, overwrite]);   // === store({key: data, key2: data});
store.get(key[, alt]);             // === store(key);
store.getAll();                    // === store();
store.clear();                     // === store(false);
store.has(key);                    // returns true or false
store.remove(key);                 // removes key and its data
store.each(callback);              // callback receives key, data, index args
store.keys();                      // returns array of keys
store.key(index);                  // return key at index
store.size();                      // number of keys, not length of data
store.clearAll();                  // clears *ALL* areas

Passing in false for the optional overwrite parameters will cause set actions to be skipped if the storage already has a value for that key. All set action methods return the previous value for that key, by default. If overwrite is false and there is a previous value, the unused new value will be returned.

All of these use the browser's localStorage (aka "local"). Using sessionStorage merely requires calling the same functions on store.session:

store.session("addMeTo", "sessionStorage");
store.local({lots: 'of', data: 'altogether'});// store.local === store :)

All the specific get, set, etc. functions are available on both store.session and store.local, as well as any other storage facility registered via store.area(name, customStorageObject) by an extension, where customStorageObject must implement the Storage interface. This is how store.old.js extends store.js to support older versions of IE and Firefox.

If you want to put stored data from different pages or areas of your site into separate namespaces, the store.namespace(ns) function is your friend:

var cart = store.namespace('cart');
cart('total', 23.25);// stores in localStorage as 'cart.total'
console.log(store('cart.total') == cart('total'));// logs true
console.log(store.cart.getAll());// logs {total: 23.25}
cart.session('group', 'toys');// stores in sessionStorage as 'cart.group'

The namespace provides the same exact API as store but silently adds/removes the namespace prefix as needed. It also makes the namespaced API accessible directly via store[namespace] (e.g. store.cart) as long as it does not conflict with an existing part of the store API.

The 'namespace' function is one of two "extra" functions that are also part of the "store API":

store.namespace(prefix[, noSession]);// returns a new store API that prefixes all key-based functions
store.isFake();// is this storage persistent? (e.g. is this old IE?) 

If localStorage or sessionStorage are unavailable, they will be faked to prevent errors, but data stored will NOT persist beyond the life of the current document/page. Use the store.old.js extension to add persistent backing for the store API in older browsers.

Extensions & Experiments

Documentation on these is yet to be written. Some have tests in the repo already. Contributions are welcome, of course.

• store.old.js - Add working localStorage and sessionStorage polyfills for older browsers
• store.cache.js - To make data expire, pass a number of minutes as the overwrite param on set() calls
• store.bind.js - Better, cross-browser storage event handling (in browsers that have such events)
• store.quota.js - Add handlers for quota errors, experiments in measuring data use
• store.overflow.js - Short demo extension that probably has no legitimate use case.

Release History

• 2010-02-10 v0.1 (extraction from esha.js)
• 2010-05-25 v1.0 (internal release)
• 2013-04-09 v2.0.3 (public)

Store vs Store

When i went to publish this on NPM i discovered another store.js by Marcus Westin. To my surprise, even our APIs had notable overlap. His has fewer features and includes superior support for IE 6/7 in the main lib. I contacted him with the idea of merging the featuresets, but we agreed it wouldn't work. He sees his library as a temporary polyfill meant to fade away with IE 6/7. This project is meant to always be useful, as a better way to use localStorage, with polyfilling as an extension. I do hope to incorporate IE 6/7 improvements from the other store.js into store.old.js at some point, but it is not a priority.

Until such time as Marcus retires his polyfill, i will continue to publish on Bower as 'store' and NPM as 'store2'. My apologies for any confusion this causes.