Storing Information

In Jinaga, information is stored in facts. Facts are immutable. That means that once you create one, you don't change it. Instead, you just create more facts.

Create a simple top-level fact.

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

  constructor(
    public domain: string
  ) { }
}

const site = await j.fact(new Site('qedcode.com'));

Try it

Create a fact with a single predecessor. Why is this called a predecessor? Because it comes before. We have to have a site before we can write a blog post.

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

  constructor(
    public createdAt: Date | string,
    public site: Site
  ) { }
}

const post = await j.fact(new Post(
  new Date(),     // Will be converted to an ISO string, such as "2018-12-23T22:46:02.487Z".
  site            // Site is the result of the previous j.fact.
));

Try it

You may be feeling that Jinaga facts are upside down. Typically, a JSON object contains its children. A site should contain its posts, not the other way around! But a Jinaga fact contains its parent. What's going on with that?

This all stems from the fact that Jinaga facts are immutable. You cannot change a fact. If a site contained an array of posts, then you would never be able to add another post. And so the relationship has to be flipped. A child knows its parent, because that parent relationship never changes.

To find all of the children of a fact, you need to write a query. By the way, we call these children successors, as you will soon see.