sessionStorage

gistfile1.js

// Initialize
var sds = new SessionDataStore();
// Store simple string
sds.set('foo', 'bar');
// Store object
sds.set('testobject', { foo: "bar" } );
// Get value back (will be a proper object, not just string)
var val = sds.get('testobject');
// Copy something
sds.copy('foo', 'foo2');
// Rename things
sds.rename('foo2', 'foo3');
// Check for something
if (sds.has('foo3')) { ... }
// Remove
sds.remove('foo3');
// Clear all
sds.clear();


// Base data store
function BaseDataStore()
{
    // Private property for storage type
    var storageType = '';
 
    // Set storage type
    this.setStorageType = function(type)
    {
        storageType = type;
    }
 
    // Get storage type
    this.getStorageType = function()
    {
        return storageType;
    }
 
    // Private method to check HTML5 LS/SS
    var checkHtml5 = function()
    {
        var ok = ('sessionStorage' in window && window['sessionStorage'] !== null &&
                'localStorage' in window && window['localStorage'] !== null);
        if (!ok)
        {
            throw 'Error: sessionStorage and/or localStorage are not supported.';
        }
    }
 
    // Public method to store key/value
    this.set = function(key, value)
    {
        checkHtml5();
 
        // Always serialize as JSON
        value = JSON.stringify(value);
 
        // Store in SS or LS
        if (storageType == 'session')
        {
            window.sessionStorage.setItem(key, value);
        }
        else
        {
            window.localStorage.setItem(key, value);
        }
    }
 
    // Public method to get value by key
    this.get = function(key)
    {
        checkHtml5();
 
        // Retrieve from SS or LS
        if (storageType == 'session')
        {
            var val = window.sessionStorage.getItem(key);
        }
        else
        {
            var val = window.localStorage.getItem(key);
        }
 
        return eval('(' + val + ')');
    }
 
    // Public method to wipe LS/SS
    this.clear = function()
    {
        checkHtml5();
 
        if (storageType == 'session')
        {
            window.sessionStorage.clear();
        }
        else
        {
            window.localStorage.clear();
        }
    }
 
    // Check if given key exists
    this.has = function(key)
    {
        checkHtml5();
 
        if (storageType == 'session')
        {
            var value = window.sessionStorage.getItem(key);
        }
        else
        {
            var value = window.localStorage.getItem(key);
        }
 
        value = eval('(' + value + ')');
 
        return (value != null && value != undefined);
    }
 
    // Copies the value of the first key to the second key.
    this.copy = function(source, target)
    {
        var value = this.get(source);
        this.set(target, value);
    }
 
    // Renames the first key to the second key.
    this.rename = function(source, target)
    {
        var value = this.get(source);
        this.remove(source);
        this.set(target, value);
    }
 
    // Removes the given key/value, from HTML5 localStorage if available,
    // otherwise from a cookie.
    this.remove = function(key)
    {
        checkHtml5();
 
        if (storageType == 'session')
        {
            window.sessionStorage.removeItem(key);
        }
        else
        {
            window.localStorage.removeItem(key);
        }
    }
}
 
// Session storage data store
SessionDataStore.prototype = new BaseDataStore;
SessionDataStore.prototype.constructor = SessionDataStore;
function SessionDataStore() {
    this.setStorageType('session');
}
 
// Locale storage data store
LocalDataStore.prototype = new BaseDataStore;
LocalDataStore.prototype.constructor = LocalDataStore;
function LocalDataStore() {
    this.setStorageType('local');
}