Named

Use ft.Named to add names to types for use in error messages. This is especially useful for large unions that can otherwise have very long error messages.

import * as ft from "funtypes";

const UserSchema = ft.Named("User", ft.Object({
  type: ft.Literal("USER"),
  id: ft.Number,
  name: ft.String,
}));

const PostSchema = ft.Named("Post", ft.Object({
  type: ft.Literal("POST"),
  id: ft.Number,
  title: ft.String,
}));

export const DbObjectSchema = ft.Union(
  UserSchema,
  PostSchema,
);
// => ft.Codec<{ type: "USER"; id: number; name: string } | { type: "POST"; id: number; title: string }>

export type DbObjectType = ft.Static<typeof DbObjectSchema>;
// => { type: "USER"; id: number; name: string } | { type: "POST"; id: number; title: string }


// ✅ Instead of printing out the full type, it just refers to sub-types by name
assert.deepEqual(
  ft.showType(DbObjectSchema),
  "User | Post"
);

Other than improving error messages, ft.Named should never make any difference to the behaviour of your funtypes.