In https://github.com/googleapis/gapic-generator-typescript/blob/master/README.md#making-changes-to-the-generated-code

There's an instruction on how to run the generator:

bazel run //:gapic-generator-typescript -- --help

I don't know for sure, but I suspect that the line is either missing a flag, or shouldn't have the second --

Apologies, I didn't actually test if this is broken.