I have made negative experience with using a custom swagger-codegen [0] template - the library is quite diffuse with no clear direction in which PRs are merged and which aren't, making it a mess to read and extend. I have however, managed to generate the exact Typescript bindings I wanted using it.

In contrast, I have been using NSwag [1] to generate C# client code with far greater comfort, and it seems to support multiple Typescript clients already.

[0] https://github.com/swagger-api/swagger-codegen [1] https://github.com/RSuter/NSwag