The project I am working on is about 30K lines of code and takes about 20 seconds for a full compile. Before I installed the plugin, it was about a minute and a half; and before we converted everything over to TypeScript and were still using Babel it was around 60 seconds. So I consider myself lucky.

Plus, a project that large would be vastly harder without strong *mandatory* type checking. I would not consider using anything less.

As far as type definition packages, it hasn’t been a problem for me. I think out of 50 dependencies that we have, there’s only one or two that we don’t have type definitions for.