// Maybe[Nothing, Just]
class Maybe {
  constructor(maybe) { this.maybe = maybe }

  static of(value) {
    if (this.isNothing()) {
      return new Nothing
    }
    return Just.of(this.value)
  }

  isNothing = () => !!this.maybe
}

// Just
class Just {
  construcor(value) { this.value = value }

  static of = value => new Just(value)

  map = f => Just.of(f(this.value))

  bind = f => this.map(f).join()

  join = () => this.value

  isJust = () => true

  isNothing = () => false

  orSome = val => this.value
}

// Nothing
class Nothing {
  construcor(value) {}

  static of = value => new Nothing

  map = f => this

  bind = f => this

  isJust = () => false

  isNothing = () => true

  orSome = val => val
}