Modern Front-End Development for Rails, Second Edition: config file pops out of nowhere (page 18)

The page starts with “TypeScripts uses a configuration file at tsconfig.json. Here’s the one we’ll start with” and then it gives the file content. I found this step surprising. I’ve started from chapter_01/02 code and followed the mentioned commands like yarn add --dev typescript..., but no such config file appeared for me. Did I miss some command that needed to be run after adding typescript?

The config file seems way too verbose/generic to be typed in manually. E.g. I don’t need to manually create config/environments/development.rb. If this is a standard configuration file (that can’t be autocreated for some reason upon addition of typescript?) maybe an extra mention of “TypeScript uses a configuration file at tsconfig.json (the initial file can be found on The parts that were modified are highlighted below” or something similar?