Promised Storage is basically a port of Mozilla's async_storage.js to Promises.
With Promised Storage you can store data in a persistent Key/Value database in the browser similarly to how you do it with localStorage but in a non-blocking way (localStorage methods block the main thread). It does so by leveraging the more powerful IndexedDB database behind the scenes.
Usage
For example:
var p = promisedStorage;p;
License
Apache 2.0