Many see and use the https://arcg.is/ links to access wordy URLs describing some ArcGIS site.
Because of reasons, I wish to store my individual records' URL in a short-ish String field.
They may be created by placing the original, "long URL" after the equals sign below:
https://arcg.is/prod/shorten?longUrl=__________________________________
A .json file will be returned with the shortened URL included.
BUT, it appears that if the long URL contains extra parameters like "extent," they seem to be ignored.
<EDIT>
I found the solution somewhere between the Dev Pages and https://doc.arcgis.com/en/web-appbuilder/latest/manage-apps/app-url-parameters.htm
Your long URL needs to be encoded to be properly accepted in full.
In my case, that meant replacing a few characters with their %xy equivalents:
Encoded_longURL=LongURL.replace("&","%26")
Encoded_longURL=Encoded_longURL.replace("=","%3D")
Encoded_longURL=Encoded_longURL.replace(",","%2C")
I'm happy to report that it's working now!!