Reader example (TODO: improve simplicity)

example-reader.ts

interface User {
  name: string
}

const generateId = () => (Math.random() * 10).toString();
const depsTest = {
  env: 'testing',
  db: {
    selectAll: (tableName: string) => [],
    select: (x: { id: string, name: string }) => x, // do nothing
    insert: (id: string, user: User) => ({ ...user, id }),
  },
  tracking: {
    toAnalytics(id: string) {
      console.log(id);
      return id;
    }
  },
  generateId
}
type Env = typeof depsTest;

const save = (user: User) => ReaderClass(({ db, generateId }: Env) =>
  db.select(db.insert(generateId(), user))
) // { id: string, name: string }

const track = (userId: string) => ReaderClass(({ tracking }: Env) => tracking.toAnalytics(userId))
const saveUserToDB = (user: User) =>
  save(user) // save to db
    .flatMap(user => track(user.id)) // after saving, hit Analytics
    .map(parseInt) // additional logic
    .map(Math.ceil) // additional logic

console.log('YHA ', saveUserToDB({ name: 'Jihad' }).run(depsTest));