Class
O.LocalStorage
- Extends
- O.Object
LocalStorage provides an observable object interface to the local/session storage facilities provided by modern browsers. Essentially, you can treat it as an instance of O.Object whose values persists between page reloads (and between browser sessions if not set to session-only).
Since data is serialised to a string for storage, only native JS types should be stored; class instances will not be restored correctly.
/*global location, sessionStorage, localStorage */
"use strict";
( function ( NS, undefined ) {
var dummyStorage = {
setItem: function () {},
getItem: function () {}
};
var LocalStorage = NS.Class({
Extends: NS.Object,Constructor
O.LocalStorage( name, sessionOnly )
Parameters
| name | String The name of this storage set. Objects with the same name will overwrite each others' values. |
|---|---|
| sessionOnly | Boolean Optional Should the values only be persisted for the session? |
init: function ( name, sessionOnly ) {
this._name = name + '.';
this._store = location.protocol === 'file:' ? dummyStorage :
sessionOnly ? sessionStorage : localStorage;
LocalStorage.parent.init.call( this );
},
get: function ( key ) {
if ( !( key in this ) ) {
var item;
// Firefox sometimes throws and error
try {
item = this._store.getItem( this._name + key );
} catch ( error ) {}
return item ? ( this[ key ] = JSON.parse( item ) ) : undefined;
}
return LocalStorage.parent.get.call( this, key );
},
set: function ( key, value ) {
// If we exceed the storage quota, an error will be thrown.
try {
this._store.setItem( this._name + key, JSON.stringify( value ) );
} catch ( error ) {}
return LocalStorage.parent.set.call( this, key, value );
}
});
NS.LocalStorage = LocalStorage;
}( O ) );