The article doesn't go into how to integrate TypeScript in the monorepo for development - what we do on the Yarn repository is that we point all the package.json `main` fields to the TypeScript sources, then use `publishConfig.main` to update it to the JS artifacts right before being published.
This way, we can use babel-node or ts-node to transparently run our TS files, no transpilation needed.
This way, we can use babel-node or ts-node to transparently run our TS files, no transpilation needed.