Step 3: Discover models

Thinking in models

You application will certainly manipulate concepts that exist in real life. A blog is about managing Authors, Posts, Comments. A restaurant website is about managing Menus, Reservations, Payments.

In Vulcan, we call those concepts "models": they are modelling the real world, using JavaScript.

In real-life, an Author is a human-being, with an education level, professionnal experiences, personnal tastes... A very complicated object! In Vulcan, an Author will be a JSON file, that describes the author firstName, lastName, and list of publications, and also a few other information like who can create/update author's data.

We only keep the "fields" that matters for our web application.

Describing a model using a schema

Vulcan provides a Sample model in src/vulcan-demo/models/sampleModel.ts. Open this file and take a look at it.

The base fields

All models will have:

• an _id: this is the document unique identifier in the Mongo database
• an userId: this is the id of the user that created the document. This special field will be used to tell who "owns" this document
• timestamps (createdAt, updatedAt): those information are added by Mongo when creating the document. createdAt is the most useful, because it lets us sort documents by creation date.

Your custom fields

Of course, you can also add your custom fields to the model. A great way to discover Vulcan possibilities is to press ctrl+space, within a field: it will show you all possible fields, thanks to TypeScript typings.

// Example of a custom field in a model
  firstName: {
    type: String,
    optional: true,
    canRead: ["guests"],
    canUpdate: ["admins", "owners"],
    canCreate: ["admins", "owners"],
  },

The model provides a lot of information. In this example, the firstName is an optional, string value. We also see that everybody can see the firstName, but only the Author himself or an admin can modifiy it ("owners" permission).

Export your model

The schema describe all the fields of a model. But a model is more than just its field, the same way an Author is not just a name and a list of publication.

After you have defined your schema, you can use the createGraphqlModel to give it life. You can configure model-level permissions, like who can see or update documents of this model.

export const modelDef: CreateGraphqlModelOptionsShared = {
  name: "sample",
  schema,
  graphql: {
    typeName,
    multiTypeName,
  },
  permissions: {
    canCreate: ["members"],
    canUpdate: ["owners", "admins"],
    canDelete: ["owners", "admins"],
    canRead: ["members", "admins"],
  },
};
export const SampleModel = createGraphqlModel(modelDef);

Vulcan automates a lot of things based on your model:

• generating the corresponding GraphQL server (to provide data to any app)
• generating the corresponding GraphQL client (to get data in your app)
• generating an admin area, etc.

Read 🔥Vulcan Fire documentation for more info.

Always remember to export your model in src/models/index to activate this automated generation.

Go to step 4

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