this isn't a fair comparison. It fails to account for what happens after the files are downloaded, which is where overall js code size has an outsized effect.

I think people have been including jQuery just fine for the last decade.

Yes, but jquery is much smaller than an empty scala.js app. jquery is about 25kb gzipped and minified (the other comment used the raw size) whereas scala js is 45kb for an empty application.

TBH, You don't use scala.js to write hello world apps. I'm much more curious how Scala.js handles a 100Kloc app, but I haven't seen any data on that.