State Machine in Javascript

post.js

const STATUS_DRAFT = "STATUS_DRAFT"
const STATUS_PUBLISHED = "STATUS_PUBLISHED"
const STATUS_UNPUBLISHED = "STATUS_UNPUBLISHED"

function createPost() {
  return {
    status: STATUS_DRAFT
  }
}

function publishPost(post) {
  post.status = STATUS_PUBLISHED
}

function unpublishPost(post) {
  post.status = STATUS_UNPUBLISHED
}