Post-emitter hooks?

[cmars]

Is there a way to add post-processing hooks to an emitter? I want to post-process the generated OpenAPI, and I can do this by orchestrating Typespec myself with custom scripts, but it would be useful to be able to trigger a JS/TS function from Typespec itself so that it always executes after the emitter completes.

Then we could share that Typespec library across our org, and generate consistent custom output with it.