Adds new tracking interface for snowplow

This will ultimately replace the stats.js that
exists in EE.

1 files changed, 45 insertions, 48 deletions

diff --git a/doc/development/fe_guide/event_tracking.md b/doc/development/fe_guide/event_tracking.md
index 716f6ad7f92..1e6287d8f6d 100644
--- a/doc/development/fe_guide/event_tracking.md
+++ b/doc/development/fe_guide/event_tracking.md
@@ -1,79 +1,76 @@
 # Event Tracking
 
-We use [Snowplow](https://github.com/snowplow/snowplow) for tracking custom events (available in GitLab [Enterprise Edition](https://about.gitlab.com/pricing/) only).
+We use a tracking interface that wraps up [Snowplow](https://github.com/snowplow/snowplow) for tracking custom events. Snowplow implements page tracking, but also exposes custom event tracking.
 
-## Generic tracking function
-
-In addition to Snowplow's built-in method for tracking page views, we use a generic tracking function which enables us to selectively apply listeners to events.
-
-The generic tracking function can be imported in EE-specific JS files as follows:
+The tracking interface can be imported in JS files as follows:
 
 ```javascript
-import { trackEvent } from `ee/stats`;
+import Tracking from `~/tracking`;
 ```
 
-This gives the user access to the `trackEvent` method, which takes the following parameters:
+## Tracking in HAML or Vue templates
 
-| parameter        | type   | description                                                                                                                                                                                                                                                                                                                            | required |
-| ---------------- | ------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------- |
-| `category`       | string | Describes the page that you're capturing click events on. Unless infeasible, please use the Rails page attribute `document.body.dataset.page` by default.                                                                                                                                                                              | true     |
-| `eventName`      | string | Describes the action the user is taking. The first word should always describe the action. For example, clicks should be `click` and activations should be `activate`. Use underscores to describe what was acted on. For example, activating a form field would be `activate_form_input`. Clicking on a dropdown is `click_dropdown`. | true     |
-| `additionalData` | object | Additional data such as `label`, `property`, and `value` as described [in our Feature Instrumentation taxonomy](https://about.gitlab.com/handbook/product/feature-instrumentation/#taxonomy).                                                                                                                                          | false    |
+To avoid having to do create a bunch of custom javascript event handlers, when working within HAML or Vue templates, we can add `data-track-*` attributes to elements of interest. This way, all elements that have a `data-track-event` attribute to automatically have event tracking bound.
 
-Read more about instrumentation and the taxonomy in the [Product Handbook](https://about.gitlab.com/handbook/product/feature-instrumentation).
-
-### Tracking in `.js` and `.vue` files
+Below is an example of `data-track-*` attributes assigned to a button in HAML:
 
-The most simple use case is to add tracking programmatically to an event of interest in Javascript.
+```haml
+%button.btn{ data: { track_event: "click_button", track_label: "template_preview", track_property: "my-template", track_value: "" } }
+```
 
-The following example demonstrates how to track a click on a button in Javascript by calling the `trackEvent` method explicitly:
+We can then setup tracking for large sections of a page, or an entire page by telling the Tracking interface to bind to it.
 
 ```javascript
-import { trackEvent } from `ee/stats`;
+import Tracking from '~/tracking';
 
-trackEvent('dashboard:projects:index', 'click_button', {
-    label: 'create_from_template',
-    property: 'template_preview',
-    value: 'rails',
+// for the entire document
+new Tracking().bind();
+
+// for a container element
+document.addEventListener('DOMContentLoaded', () => {
+  new Tracking('my_category').bind(document.getElementById('my-container'));
 });
+
 ```
 
-### Tracking in HAML templates
+When you instantiate a Tracking instance you can provide a category. If none is provided, `document.body.dataset.page` will be used. When you bind the Tracking instance you can provide an element. If no element is provided to bind to, the `document` is assumed.
 
-Sometimes we want to track clicks for multiple elements on a page. Creating event handlers for all elements could soon turn into a tedious task.
+Below is a list of supported `data-track-*` attributes:
 
-There's a more convenient solution to this problem. When working with HAML templates, we can add `data-track-*` attributes to elements of interest. This way, all elements that have both `data-track-label` and `data-track-event` attributes assigned get marked for event tracking. All we have to do is call the `bindTrackableContainer` method on a container which allows for better scoping.
+| attribute             | required | description |
+|:----------------------|:---------|:------------|
+| `data-track-event`    | true     | Action the user is taking. Clicks should be `click` and activations should be `activate`, so for example, focusing a form field would be `activate_form_input`, and clicking a button would be `click_button`. |
+| `data-track-label`    | false    | The `label` as described [in our Feature Instrumentation taxonomy](https://about.gitlab.com/handbook/product/feature-instrumentation/#taxonomy) |
+| `data-track-property` | false    | The `property` as described [in our Feature Instrumentation taxonomy](https://about.gitlab.com/handbook/product/feature-instrumentation/#taxonomy)
+| `data-track-value`    | false    | The `value` as described [in our Feature Instrumentation taxonomy](https://about.gitlab.com/handbook/product/feature-instrumentation/#taxonomy). If omitted, this will be the elements `value` property or an empty string. For checkboxes, the default value will be the element's checked attribute or `false` when unchecked. 
 
-Below is an example of `data-track-*` attributes assigned to a button in HAML:
 
-```ruby
-%button.btn{ data: { track_label: "template_preview", track_property: "my-template", track_event: "click_button", track_value: "" } }
-```
-
-By calling `bindTrackableContainer('.my-container')`, click handlers get bound to all elements located in `.my-container` provided that they have the necessary `data-track-*` attributes assigned to them.
+## Tracking in raw Javascript
 
-```javascript
-import Stats from 'ee/stats';
+Custom events can be tracked by directly calling the `Tracking.event` static function, which accepts the following arguments:
 
-document.addEventListener('DOMContentLoaded', () => {
-  Stats.bindTrackableContainer('.my-container', 'category');
-});
-```
+| argument   | type   | default value              | description |
+|:-----------|:-------|:---------------------------|:------------|
+| `category` | string | document.body.dataset.page | Page or subsection of a page that events are being captured within. |
+| `event`    | string | 'generic'                  | Action the user is taking. Clicks should be `click` and activations should be `activate`, so for example, focusing a form field would be `activate_form_input`, and clicking a button would be `click_button`. |
+| `data`     | object | {}                         | Additional data such as `label`, `property`, and `value` as described [in our Feature Instrumentation taxonomy](https://about.gitlab.com/handbook/product/feature-instrumentation/#taxonomy). These will be set as empty strings if you don't provide them. |
 
-The second parameter in `bindTrackableContainer` is optional. If omitted, the value of `document.body.dataset.page` will be used as category instead.
+Tracking can be programmatically added to an event of interest in Javascript, and the following example demonstrates tracking a click on a button by calling `Tracking.event` manually.
 
-Below is a list of supported `data-track-*` attributes:
+```javascript
+import Tracking from `~/tracking`;
 
-| attribute             | description                                                                                                                                                                                                     | required |
-| --------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------- |
-| `data-track-label`    | The `label` in `trackEvent`                                                                                                                                                                                     | true     |
-| `data-track-event`    | The `eventName` in `trackEvent`                                                                                                                                                                                 | true     |
-| `data-track-property` | The `property` in `trackEvent`. If omitted, an empty string will be used as a default value.                                                                                                                    | false    |
-| `data-track-value`    | The `value` in `trackEvent`. If omitted, this will be `target.value` or empty string. For checkboxes, the default value being tracked will be the element's checked attribute if `data-track-value` is omitted. | false    |
+document.getElementById('my_button').addEventListener('click', () => {
+  Tracking.event('dashboard:projects:index', 'click_button', {
+    label: 'create_from_template',
+    property: 'template_preview',
+    value: 'rails',
+  });
+})
+```
 
-Since Snowplow is an Enterprise Edition feature, it's necessary to create a CE backport when adding `data-track-*` attributes to HAML templates in most cases.
 
-## Testing
+## Toggling tracking on or off
 
 Snowplow can be enabled by navigating to: