fact

Creates a new fact. This method is asynchronous. It will be resolved when the fact has been persisted. It returns the fact that was just created.

fact<T>(
    prototype: T
): Promise<T>;

Parameters

• prototype - The fact to save and share

Returns

• A promise that resolves to the fact that was just persisted

Throws

• Specify the type of the fact if the type field is not provided

Examples

Create a simple top-level fact.

const tagReact = await j.fact({
    type: 'Blog.Tag',
    name: 'React'
});

Try it

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

const post = await j.fact({
    type: 'Blog.Post',
    created: new Date(),    // Will be converted to an ISO string, such as '2018-12-23T22:46:02.487Z'.
    author: person          // Where person is the result of a previous j.fact.
});

Try it

Create a fact with multiple predecessors. Just put them in an array.

await j.fact({
    type: 'Blog.Post.Tags',
    post: post,
    tags: [tagReact, tagCss, tagMicroFrontends]
});

Try it

You can specify the predecessors inline. The predecessor facts will be persisted first. However, persistence is not guaranteed to be atomic.

await j.fact({
    type: 'Blog.Post.Tags',
    post: {
        type: 'Blog.Post',
        created: new Date(),
        author: person
    },
    tags: [{
        type: 'Blog.Tag',
        name: 'React'
    }, {
        type: 'Blog.Tag',
        name: 'CSS'
    }, {
        type: 'Blog.Tag',
        name: 'Micro-Frontends'
    }]
});

Try it

You may be feeling that Jinaga facts are upside down. Typically, a JSON object contains its children. 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 fact contained an array of children, then you would never be able to add another child. 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.