A/B tests in donate-button

[osdiab]

• We can keep an enum of experiments and possible values in a subpackage of donate-button
• When a request comes in, the Cloudflare Worker sets a cookie containing a single value, a sessionId
• The cloudflare worker also stores values for all of the available experiments into Cloudflare KV, keyed by sessionId.
• Then the donate-button bundle will do an AJAX call to a Cloudflare-worker hosted endpoint, somethign like partners.every.org/experiments
• That will return the stored object for that sessionId to the frontend, which will be saved in a React Provider in the donate-button code
• Until that call is done, the donate button will use each experiment's DEFAULT value
• We will add some behavior-tracking API endpoint (https://github.com/everydotorg/donate-button/issues/205) to record A/B test results.

[osdiab]

for now assigning to me but I hope to add someone else from Every.org to spread internal knowledge of the repo

[osdiab]

gonna abandon this for now - privacy concerns over tracking cookies on other peoples' websites is tricky.