Yes, all of these are supported in JSDoc because they are supported in TypeScript. Because JSDoc is TypeScript. You can either define your types in JSDoc comments or in .ts files.

I really mean it. You can even use the @satisfies operator like so

  /** @satisfies {Type} */

Discriminated unions, conditional types, mapped types, template literal types, etc work exactly the same way if you define them in a JSDoc comment as if you define them in a .ts file