Whyrify

Fault injection engine for whyrify.com

Inject and configure

inject snippet to website, make it not async and load as early as you can:

<script type="text/javascript" src="//s.whyrify.com/w/whyrify.min.js" />

Using WHYRIFY_CONFIG object, you can setup reporting, and fault rate (default to 5%).

<script>
  window.whyrify = window.whyrify || function() {
    (window.whyrify.q = window.whyrify.q || []).push(arguments);
  };
  whyrify('config', 'XXXX-XXXX-XXXX-XXXX-XXXX-XXXX', 0.5);
</script>
<script type="text/javascript" src="//s.whyrify.com/w/whyrify.js" />

Fault injection

Now all scripts marked with type="text/whyrify" will run by whyrify.js, eventually fail with controlled chance. Additionally you can name the feature/attribute by adding attribute data-feature="feature-x".

For example:

<script type="text/whyrify" src="https://www.googletagmanager.com/gtm.js?id='XXXXX" data-feature="GTM" />

You can also call decide to bucket feature manually:

<script>
  window.whyrify = window.whyrify || function() {
    (window.whyrify.q = window.whyrify.q || []).push(arguments);
  };
  window.whyrify("decide", "featureX", (result) => {
      if(result === "control") {
          //activate feature
      }
  });
</script>
<script type="text/javascript" src="//s.whyrify.com/w/whyrify.min.js" />

Measure

Finally, you can send conversion events by calling whyrify('link', 'conversion'), so we can validate experiment using Bayesian stats.

window.whyrify =
    window.whyrify ||
    function () {
        (window.whyrify.q = window.whyrify.q || []).push(arguments);
    };
window.whyrify("link", "conversion"); //trigger  default conversion
window.whyrify("link", "add-to-cart"); // trigger another conversion

How to use as NPM package

Install the package:

npm i @whyrify/whyrify-js

Basic usage:

import { Whyrify } from "@whyrify/whyrify-js";

const faultEngine = new Whyrify(
    "XXXX-XXXX-XXXX-XXXX-XXXX-XXXX", // measurement id
    50, // 50% chance to fail
    true, //do not watch for another scripts
);
if (faultEngine.decide("fault-injection-hero") === "control") {
    console.log("Control");
} else {
    console.log("Fault");
}
faultEngine.link("conversion");