SAM 패턴, 감수분열의 기원

let actions = {
  countBy(step) {
    step = step || 1
    model.accept({incrementBy:step})
  }
}

let model = {
  counter: 1,
  accept(proposal) {
    this.counter += (proposal.incrementBy > 0) ? proposal.incrementBy : 0
    state.render(this)
  }
}

let state = {
  render(model) {
    if (!this.nextAction(model)) {
      console.log(model.counter)
    }
  }, 

  nextAction(model) {
    if (model.counter % 2 == 0) {
      actions.countBy(1)
      return true
    } else {
      return false
    }
  }
}

actions.countBy(2)