The problem is when I add a Link item (external Url) in that document library, I cannot find an item property that stores the external Url.
Right now I get the item properties via SharePoint REST API. I checked the values of FileRef and EncodedAbsUrl, but these are URLs pointing to the SharePoint document library file, and not to the external URL.
After some investigations, I've seen in the dev tools (F12) Network tab, there's a call to https://{siteurl}/_api/SP.Utilities.ShortcutLink.GetShortcutLink(@a1)?@a1={siteUrl}/Shared%20Documents/www.dummysite.com.url which will retrieve the actual linked external URL, but this not a good option for me, since making another REST call for each item will impact my performance.
So is there any item property that I could expand to get the external URL, via REST API?