ScopedStorage: localStorage & sessionStorage per page

A simple wrapper around localStorage and sessionStorage that mimics storage per scope such as a single web page. This is done via a key prefix that is passed when constructing a ScopedStorage.

Value types are preserved by default (unlike localStorage and sessionStorage).

No key prefix (scope) can be a substring of another key prefix so generally URL paths should not be used as-is; for example, clearing the ScopedStorage of /project/ will also clear that of /project/foo/ (unless this is what you would like). If the current path is /project/foo/, you could use key prefix project-foo/ (i.e. remove any leading or trailing /, replace each remaining / with - and end with a /).

// Initiate a storage (underlying type is sessionStorage by default)
var storage = new ScopedStorage('project-foo/');

// To specify localStorage as the underlying type
var lastingStorage = new ScopedStorage('project-bar/', StorageTypes.LOCAL_STORAGE);

// For a behaviour that only returns string values (like localStorage and sessionStorage)
var allStringValueStorage = new ScopedStorage('project-bar/', StorageTypes.SESSION_STORAGE, true);

/*
Use the object the same way you would with localStorage or sessionStorage with these methods:
setItem, getItem, removeItem, clear
*/

storage.setItem('pi', 3.14);
console.log(storage.getItem('pi'));   // 3.14

storage.setItem('bar', '1.05e-34');
console.log(storage.getItem('bar'));  // '1.05e-34'

storage.removeItem('pi');

storage.clear();

TODO

• Add tests
• length property
• key method
• Benchmark against:
  • raw localStorage and sessionStorage
  • macmcmeans/localDataStorage