Message.ts

import * as Union from ‘@iadvize-oss/opaque-union;

type $Text = {
  text: string;
}

type $Image = {
  url: string;
  description: string;
}

const MessageUnion = Union.of({
  Text: Union.type<$Text>(),
  Image: Union.type<$Image>(),
});

// opaque types
export type Text = ReturnType<typeof MessageUnion.of.Text>;
export type Image = ReturnType<typeof MessageUnion.of.Image>;

// union of opaque types
export type Message = Union.Type<typeof MessageUnion>;

// constructors

export const createText = MessageUnion.of.Text;
export const createImage = MessageUnion.of.Image;

// queries

export const text = MessageUnion.Text.lensFromProp(‘text’).get;

export const url = MessageUnion.Image.lensFromProp(‘url’).get;
export const description = MessageUnion.Image.lensFromProp(‘description’).get;

export const isText = MessageUnion.is.Text;
export const isImage = MessageUnion.is.Image;

// transformations

export const addSignature = (signature: string) => MessageUnion.Text.iso.modify(
  ($text) => ({ ...$text, text: `${$text.text} - ${signature}` })
);

export const withBitlyUrl = MessageUnion.Image.lensFromProp(‘url’)
  .modify(convertToBitly);

// fold function from @iadvize-oss/foldable-helpers
const fold = MessageUnion.fold;