LocalForage – A fast and simple storage library for JavaScript

localForage is a fast and simple storage library for JavaScript. localForage improves the offline experience of your web app by using asynchronous storage (IndexedDB or WebSQL) with a simple, localStorage-like API.

localForage uses localStorage in browsers with no IndexedDB or WebSQL support. See the wiki for detailed compatibility info.

To use localForage, just drop a single JavaScript file into your page:

<scriptsrc="localforage.js"></script><script>localforage.getItem('something', myCallback);</script>

Download the latest localForage from GitHub, or install withnpm:

or bower:

bower install localforage

localForage is compatible with browserify.

Support

Lost? Need help? Try thelocalForage API documentation.

If you're stuck using the library, running the tests, or want to contribute to localForage, you can visitirc.freenode.net and head to the #localforage channel to ask questions about localForage.

The best person to ask about localForage is tofumatt, who is usually online from 8am-8pm GMT (London Time).

Callbacks vs Promises

Because localForage uses async storage, it has an async API. It's otherwise exactly the same as thelocalStorage API.

localForage has a dual API that allows you to either use Node-style callbacks or Promises. If you are unsure which one is right for you, it's recommended to use Promises.

Here's an example of the Node-style callback form:

localforage.setItem('key', 'value', function (err) {// if err is non-null, we got an errorlocalforage.getItem('key', function (err, value) {// if err is non-null, we got an error. otherwise, value is the value 
  });
});

And the Promise form:

localforage.setItem('key', 'value').then(function () {returnlocalforage.getItem('key');
}).then(function (value) {// we got our value
}).catch(function (err) {// we got an error
});

For more examples, please visit the API docs.

Storing Blobs, TypedArrays, and other JS objects

You can store any type in localForage; you aren't limited to strings like in localStorage. Even if localStorage is your storage backend, localForage automatically does JSON.parse() and JSON.stringify() when getting/setting values.

localForage supports storing all native JS objects that can be serialized to JSON, as well as ArrayBuffers, Blobs, and TypedArrays. Check theAPI docs for a full list of types supported by localForage.

All types are supported in every storage backend, though storage limits in localStorage make storing many large Blobs impossible.

Configuration

You can set database information with the config() method. Available options are driver, name, storeName, version, size, anddescription.

Example:

localforage.config({
    driver      :localforage.WEBSQL, // Force WebSQL; same as using setDriver()
    name        :'myApp',
    version     :1.0,
    size        :4980736, // Size of database, in bytes. WebSQL-only for now.
    storeName   :'keyvaluepairs', // Should be alphanumeric, with underscores.
    description :'some description'
});

Note: you must call config()before you interact with your data. This means calling config() before using getItem(), setItem(), removeItem(),clear(), key(), keys() or length().

Multiple instances

You can create multiple instances of localForage that point to different stores using createInstance. All the configuration options used byconfig are supported.

var store =localforage.createInstance({
  name:"nameHere"
});var otherStore =localforage.createInstance({
  name:"otherName"
});// Setting the key on one of these doesn't affect the other.store.setItem("key", "value");otherStore.setItem("key", "value2");

RequireJS

You can use localForage with RequireJS:

define(['localforage'], function(localforage) {// As a callback:localforage.setItem('mykey', 'myvalue', console.log);// With a Promise:localforage.setItem('mykey', 'myvalue').then(console.log);
});

Browserify and Webpack

localForage 1.3+ works with both Browserify and Webpack. If you're using an earlier version of localForage and are having issues with Browserify or Webpack, please upgrade to 1.3.0 or above.

Webpack will emit a warning about using a prebuilt javascript file which is fine. If you want to remove the warning you should exclude localforage from being parsed by webpack using the following conf :

module: {
  noParse:/node_modules\/localforage\/dist\/localforage.js/,
  loaders: [...],

TypeScript

If you have the allowSyntheticDefaultImports compiler option set to true in your tsconfig.json (supported in TypeScript v1.8+), you should use:

importlocalForagefrom"localforage";

Otherwise you should use one of the following:

import*aslocalForagefrom"localforage";// or, in case that the typescript version that you are using// doesn't support ES6 style imports for UMD modules like localForageimport localForage = require("localforage");

Framework Support

If you use a framework listed, there's a localForage storage driver for the models in your framework so you can store data offline with localForage. We have drivers for the following frameworks:

If you have a driver you'd like listed, pleaseopen an issue to have it added to this list.

Custom Drivers

You can create your own driver if you want; see thedefineDriver API docs.

There is a list of custom drivers on the wiki.

You'll need node/npm andbower.

To work on localForage, you should start byforking it and installing its dependencies. Replace USERNAME with your GitHub username and run the following:

# Install bower globally if you don't have it:
npm install -g bower# Replace USERNAME with your GitHub username:
git clone git@github.com:USERNAME/localForage.gitcd localForage
npm install
bower install

Omitting the bower dependencies will cause the tests to fail!

Running Tests

You need PhantomJS installed to run local tests. Run npm test (or, directly: grunt test). Your code must also pass thelinter.

localForage is designed to run in the browser, so the tests explicitly require a browser environment. Local tests are run on a headless WebKit (usingPhantomJS).

When you submit a pull request, tests will be run against all browsers that localForage supports on Travis CI using Sauce Labs.

This program is free software; it is distributed under anApache License.

Copyright (c) 2013-2016 Mozilla (Contributors).