tsType use export from npm package

[darcyrush]

I see from this issue that using tsType with packages seems to be possible. However I cannot seem to get this to work. The import I want to define is

import { StreamableFile } from "@nestjs/common";

The examples here only give basic examples of inbuilt Node exports

[bcherny]

There isn't a great way to do this today. Proposals welcome!

[vihangm]

I found a workaround that happens to work but isn't elegant.
one can override bannerComment and add the import to it. this just gets added to the top of the generated file and happens to work.

a better solution would be create a flag similar to bannerComment to specify imports (and maybe also take a raw string in banner comment and force it into a comment block)