Creating Your First Model

If you are more of a "learn-by-example" person, you can first check out the examples first.

Once you have everything set-up and ready, let's go ahead and write our first data model definition.

Models in Aida are just JavaScript objects. Although the fact that we are using a programming language for the model definition might seem weird, considering it is not interoperable compared to a format such as JSON, it is much more powerful. It allows us to do things like referencing other models, writing validation code, writing fake data definition, and it allows us to utilize the entire JS ecosystem. This might change in the future to something more interoperable as the tool evolves.

Let's create a very simple User model with an id and email property. Go to the models folder, create a User folder, and inside it create a file named User.core.js. This is where we define the core properties of a model.

const User = {
  id: {
    vtype: 'string',
  },
  email: {
    vtype: 'string',
  }
};

exports.default = User;

Each model property has to contain a type, named vtype (we didn't simply use type in order to avoid collisions with model properties named type). You can find all defined types that can be used as a value of vtype here. The vtype property denotes that the property is a primitive. Aida can recognize whether a property is a composite or a primitive by the presence of the vtype property on a primitive. Let's now add a composite nested object, an address property to the User model.

const Address = {
  city: {
    vtype: 'string',
  },
  street: {
    vtype: 'string',
  }
}

//...The User code

Let's add the address property to our User object now.

const User = {
  //...Existing properties
  address: Address,
};

exports.default = User;

Simple as that! We can put the Address model in another file and use it throughout the entire stack, having a consistent definition of an address. We can also cherry-pick only the properties we want instead of the entire Address model and it is very easy to do so, as it is just a JavaScript object.

Let's try specifying another composite property, an array of some type:

const User = {
  ..., //All other properties
  phoneNumbers: [{vtype: 'string'}],
};

exports.default = User;

Doing that defined phoneNumbers as a list of strings. You can also have nested objects in your data models as deep as it is necessary.

We have seen how we can define a model with both primitive and composite properties, but we can't do much with these models (except generate type definitions and schemas for different languages and technologies). Let's spice things up a bit and enrich our models next.