Co-founder of Appsmith here. Thanks a lot for mentioning our project.

We love Typescript and chose it to take advantage of static type checking. At Apspmith, since we are a small team, we wanted to reduce management overheads and opted for a monorepo layout. Typescript went a long way in helping us organize the code into modules and let our build scripts compile relevant modules for each changeset.

Having said that, Appsmith has been a learning experience in efficiently running a large project with lots of files. Feel free to dig into our source code to learn from our experiences. :)