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cache.js

HTML5 localStorage with timed expiry

Why?

For ajax or heavy computational stuff that could probably be done once a minute, rather than every time the functions/events are called.

Browser support

Anything that supports localStorage. You could use a localStorage polyfill to use it with older browsers.

For brevity, the browsers that support localStorage are Firefox 3.5, Safari 4, IE8, Chrome 4+

Usage

Add cache.js to your HTML, I've included a closure compressed cache.min.js for use online.

When you're in the middle of doing some heavy ajax, you can store the response in cache.

Cache.set('a unique identifier', {foo: 'bar'});

Your key of 'a unique identifier' can now be returned using the get method.

Cache.get('a unique identifier');

=> {foo: 'bar'}

It will only be available for 10000ms (the default)

Getting a non existant key

Cache.get('will be null');
=> null

Of course, you can set the expiry on a per key basis

Cache.set('key', 'value', 5e4); // 50,000 Milliseconds

Or set a global expiry to be used for all caches

Cache.expiry = 5e4 // 50K ms

Pulling it all together, you might do something like this:

var cache = Cache.get("/url");
if(cache) return cache;

$.get("/url", function (response) {
  Cache.set("/url", response);
  // Do something awesome with your responseText    
});

Optional 'get' function if value is null

Often, you'll want to do something if the value is not cached. Pass a function to the get function:

var result = Cache.get('empty key', function(key) {
  return 'bacon';
});
// `result` is now 'bacon' since there was no stored value.

For example, you could execute an Ajax call if the local storage is empty. Here's the earlier example with a cleaner style:

return Cache.get("/url", function(key) {
  return $.get(key, function (response) {
    Cache.set(key, response);
    return response;
  });
});

Bugs / Contributions

  • Report a bug
  • To contribute, or send an idea wither github message me or fork the project.
  • If you're changing functionality, please perouse the test/ directory first.
  • You can run the tests on a Mac by running rake test, otherwise, just open suite.html in a browser

Build

If you're on a mac, run rake build—You'll need the google closure compiler installed, but it will package cache.js into cache.min.js. Then it'll automagically make a commit describing what you've done. Magic.

Hall of fame

These contributors will be upheld in the record books as those of fine character and dignity. Eternal greatness ensues.