docs/quickstart/nested_types_example.md
# Nested types example
The [introductory example](README.md) features a standalone
class. Let's look at a more involved example that builds on top of that:
```JSON
{
"givenName": "Javier",
"familyName": "Cejudo",
"pets": [
{
"name": "Robbie"
}
]
}
```
Notice that the data contains a list of pets (`Animal`).
Again, our goal is to parse JSON into JavaScript classes to be able to do
things like
```js
const person1 = M.fromJSON(Person, personJson)
person1.fullName() // => 'Javier Cejudo'
person1.pets().get(0).speak() // => 'my name is Robbie!'
```
*Note: pets() returns a `Modelico.List`, which has a `get` method, but little
more. To `map`, `filter` or perform other operations, you will need to grab
the underlying array with `.inner()`. See the
[proxies docs](../advanced/proxies.md) for a way to use methods and properties of
the inner structure directly.*
To achieve our goal, we need a `Person` that references `Animal` within its
inner types using the `M.metadata()._` function.
```js
import M from 'modelico'
const {_, string, list} = M.metadata()
class Person extends M.Base {
fullName () {
return `${this.givenName()} ${this.familyName()}`.trim()
}
static innerTypes () {
return Object.freeze({
givenName: string(),
familyName: string(),
pets: list(_(Animal))
})
}
}
```