Percussion

Debugging tool for JS reactive programming libraries.

This library allows to visualize streams in order to debug reactive javascript programming applications. Currently supported libraries are:

• Bacon.js - https://baconjs.github.io/
• RxJS - http://reactivex.io/
• Kefir.js - https://rpominov.github.io/kefir/

Simple usage

You can just initialize constructor without options:

var percussion = new Percussion();

And then add as many streams as you want:

percussion.addStream(stream1);
percussion.addStream(stream2);
percussion.addStream(stream3);
...

Then, you will see streams represented as lines, and events represented as circles in those lines. You can mouse-hover in the circles in order to see their values in a tooltip, or click them to see their values in the browser debugger console.

Methods

You can stop debugging with:

percussion.stop();

And then recover execution with:

percussion.start();

By default, data visualization will automatically be scrolled in order to see last stream events. You can disable this in runtime with:

percussion.setAutoScroll(false);

and enable again with:

percussion.setAutoScroll(true);

Constructor options

• lineSize: Height of the stream line in px. Default: 20
• pointSize: Width of the event point in px. Default: 10
• speed: Speed of stream visualization in px/sample. Default: 20
• timeout: Time of each sample in ms. Default: 250
• autoScroll: Whether if data visualization will automatically do scroll or not. Default: true
• print = Whether if event values will be printed in the stream visualization or not. Default: false
• colors: Array of colors for events in each stream. Will be repeated cyclically. Default: ['#F00', '#0F0', '#00F']
• textColors = Array of text colors for events in each stream (visible only if print == true). Should be the same size as colors, and also, will be repeated cyclically. Default: ['#FFF', '#FFF', '#FFF']
• position = HTML Element where data visualization will be injected. Notice this needs to be a pure Element, so if you use libraries like jQuery, you need to convert it (i.e.: $('#canvas')[0]). Default: document.body

Example:

var percussion = new Percussion(
  {
    position: document.getElementById('canvas'),
    speed: 200
  }
);

Contributors

grisendo: Francisco J. Cruz Romanos grisendo@gmail.com

License

MIT License