[ENHANCEMENT REQUEST] custom event when missing third-party cookies #28
Description
Problem
When using <tableau-viz token="my JWT" /> with Tableau Cloud, if the user's browser doesn't have third-party cookies enabled, the custom element will create the iframe and try to set a cookie, fail, and display a "Sign in to Tableau Cloud" page.
I would like to detect this case and show a message to users that they have to enable third-party cookies. I cannot because there is no event fired in this case.
The best I can do is set a timeout and detect the absence of a firstvizsizeknown event. But that's error-prone. If I set the timeout too short, users on a slow connection (or when Tableau's servers are overloaded) will see the third-party cookies message by mistake. If I set the timeout too long, users will see "Sign in to Tableau Cloud" for too long before our message and get confused.
Request
Trigger a vizloaderror event when Tableau detects it cannot fetch the visualization due to a missing cookie.