Different developers have different needs, hence the different modules on NPM as there’s more than 1 right way to go about it, and Twitch provide you all the documentation you need to access the API in whatever way might be most suitable to you.
I don’t use yaml, but looking at a quick google it looks to just be a simple specification of the expected inputs/outputs for the api. I’m trying to understand what’s stopping you making it yourself based on the documentation Twitch has provided?