Pegasus

Load data while still loading other scripts

With Pegasus, you can do this

Instead of this

Pegasus is a tiny lib (0.2 kB min/gzip) that lets you load data while loading other scripts.

Using this technique, you can reduce the time to display data in single page apps without touching the server.

Install

$ bower install pegasus

Demo

http://typicode.github.io/pegasus

Benchmark

Average time to display data on the demo site.

	jQuery only	jQuery + Pegasus
EDGE	3000 ms	2100 ms
3G	860 ms	640 ms
DSL	270 ms	230 ms

Note: jQuery is used for illustration only, you can use Pegasus with any other Javascript library.

Usage example

<!-- Load (or embed) Pegasus and start request(s) before loading any other script -->
<script src="pegasus.min.js"></script>

<!-- Request will start as soon as Pegasus is loaded -->
<script>
  var request = pegasus('http://api.example.com');
</script>

<!-- Load your app lib(s) -->
<script src="jquery.js"></script>

<!-- Use the request promise to retrieve data in your app -->
<script>
  request.then(
    // success handler
    function(data, xhr) {
      // do something useful like
      $('#data').text(JSON.stringify(data));
    },
    // error handler (optional)
    function(data, xhr) {
      console.error(data, xhr.status)
    }
  );
</script>

Note: The same method can be applied with any other JavaScript library (Backbone, AngularJS, ...).

Tip: You can also directly embed pegasus.min.js code in your html file to save a network call (it's smaller than the Google analytics tracking code).

Support