fiji.js

Fiji is a lightweight library for proxying localStorage and sessionStorage. Since we know accessing these storage mechanisms is slower than accessing object properties, one way to realize a small performance gain, as well as introduce some caching logic, is to access a native JS data structure most of the time, only going back to sessionStorage or localStorage if the data in our object is considered stale.

This library is more of a thought experiment than a tool that is inherently useful. However, Fiji is free to use as is. Constructive feedback and suggestions are most welcome.

Usage

Create a new instance of Fiji on your page, passing in the desired options. All options are... optional. The default option values are shown below.

var fiji = new Fiji({
  ns: 'Fiji',           // The name to use for the localStorage and sessionStorage items
  ttl: 86400000,        // Number of seconds till sessionStorage item expiry
  longTtl: 2592000000,  // Number of seconds till localStorage item expiry
  debug: false          // Turn debug mode on, which enables extra logging output
});

Cache objects are stored internally with the following structure:

{
  "id": "KEY_STRING",
  "value": 12345,
  "expires": Fri Oct 31 2014 17:27:16 GMT-0400 (EDT)
  "isLongTerm": false
}

This an object for sessionStorage. The only difference for a localStorage object is that the isLongTerm property would have been set to true.

Internally, cache objects are serialized with JSON.stringify prior to being saved to sessionStorage/localStorage, and de-serialized with JSON.parse immediately after retrieval.

Cache objects are saved atomically to storage under a common namespace (Fiji by default).

API

Once you have created an instance of Fiji, referred to henceforth as fiji, you may call the following methods on it:

fiji.get(key)

Returns the value of a cache object with the given key/id. If the data is determined to be expired, the appropriate storage mechanism will be queried.

fiji.set(key, value, [isLongTerm])

Sets the value of a cache object with the given key/id, and optionally, the isLongTerm property to denote localStorage as opposed to the default, which is sessionStorage.

fiji.del(key, [confirmDeleteAll])

Deletes the cache object with the given key/id, as well as its sessionStorage/localStorage cousin. If true is passed as the optional second argument, the entire Fiji cache is reset.

fiji.list()

Returns an object representation of all cached key/value pairs. Uses fiji.keys and fiji.get to retrieve a dataset of appropriate freshness.