What are you trying to achieve?
Allow consumers of sharp to use your supported types. Maybe this applies to supported inputs too.

Have you searched for similar feature requests? yes

What would you expect the API to look like?
export formats

What alternatives have you considered?
No.

Is there a sample image that helps explain?
Here in Parcel's code they're copying your types, but like, they should be able to import this so they don't have to maintain parity
https://github.com/parcel-bundler/parcel/blob/0934f9f/packages/transformers/image/src/ImageTransformer.js#L5