Click script contains an optional callback that can be used to pass tracking parameter CID to the clien't side.

Once you visit an affiliate tracking link and land on a landing page, a Click script processes the parameters in URL and sends request "V1", returning the CID and saving it to cookie called trakdesk_cid (BEWARE, not trackdesk_cid).

This is the format of the trackdesk function with callback included:

trackdesk("robocop", "click", {}, (data) => { console.log(data.cid); });

The callback provides two parameters - data.cid and data.expiredAt

CID is then used to create conversions later on in the flow.

Expiration date is mostly just for the expiration of a cookie that is set at the same time.