Not sure if that's a sane way to do this, it's the first time I'm playing around with Swagger.

I bumped into the following link and pasted the schema from the project I integrate with. From the top 'Generate Client' menu I chose one of the TypeScript presets and it generated a minimal project where I could extract the bits I needed, interface and classes, etc.

http://editor.swagger.io/#/

I tried running your schema. Here's a small excerpt of the generated code:

export interface Bar {
    "a"?: string;
    "b": number;
    "c": Date;
    "baz"?: Baz;
}

export interface Baz {
    "d": number;
    "color": Color;
}

/**
 * 
 */
export type Color = "0" | "1" | "2";

Maybe with a bit more tweaking it can make exactly what you're looking for.

Further reading may be about tools like https://github.com/swagger-api/swagger-codegen but the online web editor is a quick and dirty way to do this.

Yes, you can easily generate Swagger and OpenAPI documents from your TypeScript types by using tsoa. The readme contains all of the setup information that you would need to start using it. It's compatible with express, hapi, koa, and more:

https://github.com/lukeautry/tsoa

(Full Transparency: I ~am~ was one of the maintainers of tsoa. But I was first a consumer of tsoa and I find it to be a great product... that's why I asked to help maintain it! :) ) I’ve since stepped back, but the new maintainers are awesome!