jinaga/test/blogModel.ts

Data management for web and mobile applications.

import { DistributionRules, User, buildModel } from "../src";

export class Blog {
  static Type = "Blog" as const;
  type = Blog.Type;

  constructor(
    public creator: User,
    public domain: string
  ) { }
}

export class Post {
  static Type = "Post" as const;
  type = Post.Type;

  constructor(
    public blog: Blog,
    public author: User,
    public createdAt: Date | string
  ) { }
}

export class Publish {
  static Type = "Publish" as const;
  type = Publish.Type;

  constructor(
    public post: Post,
    public date: Date | string
  ) { }
}

export class Comment {
  static Type = "Comment" as const;
  type = Comment.Type;

  constructor(
    public post: Post,
    public author: User,
    public text: string,
    public createdAt: Date | string
  ) { }
}

export class CommentApproved {
  static Type = "CommentApproved" as const;
  type = CommentApproved.Type;

  constructor(
    public comment: Comment,
    public approvedAt: Date | string
  ) { }
}

export const model = buildModel(b => b
  .type(User)
  .type(Blog, x => x
    .predecessor("creator", User)
  )
  .type(Post, x => x
    .predecessor("blog", Blog)
    .predecessor("author", User)
  )
  .type(Publish, x => x
    .predecessor("post", Post)
  )
  .type(Comment, x => x
    .predecessor("post", Post)
    .predecessor("author", User)
  )
  .type(CommentApproved, x => x
    .predecessor("comment", Comment)
  )
);

export const distribution = (r: DistributionRules) => r
  // Everyone can see published posts
  .share(model.given(Blog).match(blog =>
    blog.successors(Post, post => post.blog)
      .exists(post => post.successors(Publish, publish => publish.post))
  )).withEveryone()
  // The creator can see all posts and comments
  .share(model.given(Blog).select(blog => ({
    posts: blog.successors(Post, post => post.blog),
    comments: blog.successors(Comment, comment => comment.post.blog)
  }))).with(model.given(Blog).match(blog =>
    blog.creator.predecessor()
  ))
  // A comment author can see their own comments on published posts
  .share(model.given(Blog, User).match((blog, author) =>
    blog.successors(Post, post => post.blog)
      .exists(post => post.successors(Publish, publish => publish.post))
      .selectMany(post => post.successors(Comment, comment => comment.post)
        .join(comment => comment.author, author)
      )
  )).with(model.given(Blog, User).select((blog, author) =>
    author
  ));