flavoring-and-branding.ts

/** Used by Flavor to mark a type in a readable way. */
export interface Flavoring<FlavorT> {
  _type?: FlavorT;
}
/** Create a "flavored" version of a type. TypeScript will disallow mixing flavors, but will allow unflavored values of that type to be passed in where a flavored version is expected. This is a less restrictive form of branding. */
export type Flavor<T, FlavorT> = T & Flavoring<FlavorT>;

/** Used by Brand to mark a type in a readable way. */
export interface Branding<BrandT> {
  _type: BrandT;
}
/** Create a "branded" version of a type. TypeScript won't allow implicit conversion to this type */
export type Brand<T, BrandT> = T & Branding<BrandT>;

Thanks!

Going in: unional/type-plus#18