&gt; Most Scala libraries never used reflection, so most of the ecosystem &quot;just worked&quot; on Scala.js.<p>Do you have personal experience with this? I do not have hard numbers, but for me - basically none of my stack worked.<p>I had to find a new JSON parser. I had to find new validation for my form stuff. Etc. etc.<p>It wasn&#x27;t impossible, but it was a lot of work.