Nice work on the migration! I worked on the Dropbox coffeescript-to-typescript migration, and any sort of migration of that magnitude is non trivial :)

We started out with the same approach as you guys, by introducing Typescript to the company, making it possible to write code in Typescript, and encouraging teams to use it. We had an OKR to convert all of our Coffeescript to Typescript by the end of the year, though, so eventually we had to go with an automated approach to convert the rest of the files, which you can read about here: https://dropbox.tech/frontend/the-great-coffeescript-to-type...