# Composability

With **Rivet** composability, you are able to reuse fundamental pieces of your contracts, such as data types, to make them much more maintainable. We do this by leveraging CommonJS modules and compiling your contracts to JSON.

## Composing with shared types

JSON Schema has a limited number of data types that it supports. For example, string, number, boolean. However, you can build custom data type validation using the `pattern` key in JSON schema.

### Custom Data Types

You can create custom data types to share between your contracts. If you need them on multiple applications, consider using an npm module.

**Custom** `animal` **data type:**

```javascript
// types/animal.js
module.exports = {
  id: 'types.animal',
  type: 'string',
  pattern: 'cat|dog'
};
```

**Usage:**

```javascript
// example.contract.js
const animal = require('./types/animal');

module.exports = {
  title: 'Example',
  type: 'object',
  properties: {
    pet: animal,
  },
  required: ['pet']
};
```

### Rivet default types

Rivet ships with a few [pre-defined data types](/contracts/composability.md#default-types).

```javascript
const { types } = require('rivet');

module.exports = {
  title: 'Example'
  type: 'object',
  properties: {
    email: types.email,
    phone: types.phone,
  },
  required: ['email', 'phone']
};
```

## Default Types

Below are the pre-defined types and their definitions.

### `email`

```javascript
{
  "id": "types.email",
  "type": "string",
  "format": "email",
  "pattern": "^(([^<>()\\\[\\]\\\.,;:\\s@\"]+(\\.[^<>()\\[\\]\\\.,;:\\s@\"]+)*)|(\".+\"))@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}])|(([a-zA-Z\\-0-9]+\\.)+[a-zA-Z]{2,}))$"
}
```

> **Example Matches:**
>
> ```
> bob@sho.rt
> bob-villa@sho.rt
> bob@example.com
> bob.villa@example.com
> bob+villa@example.com
> ```

### `phone`

```javascript
{
  "id": "types.phone",
  "type": "string",
  "pattern": "^(?:(?:\\+?1\\s*(?:[.-]\\s*)?)?(?:\\(\\s*([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9])\\s*\\)|([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]))\\s*(?:[.-]\\s*)?)?([2-9]1[02-9]|[2-9][02-9]1|[2-9][02-9]{2})\\s*(?:[.-]\\s*)?([0-9]{4})(?:\\s*(?:#|x\\.?|ext\\.?|extension)\\s*(\\d+))?$"
}
```

> **Example Matches:**
>
> ```
> 12345678900
> +12345678900
> 2345678900
> (234) 567-8900
> (555)-555-5555
> 555-555-5555
> +1-555-532-3455
> ```

### `jwt`

```javascript
{
  "id": "types.jwt",
  "type": "string",
  "pattern": "^[A-Za-z0-9-_=]+\\.[A-Za-z0-9-_=]+\\.?[A-Za-z0-9-_.+/=]*$"
}
```

> **Example Matches:**
>
> ```
> ABC3EFGH.IJKLMN7PQRSTU.VWXYZ1234567890
> ```

### `uri`

```javascript
{
  "id": "types.uri",
  "type": "string",
  "pattern": "([A-Za-z][A-Za-z0-9+\\-.]*):(?:(//)(?:((?:[A-Za-z0-9\\-._~!$&'()*+,;=:]|%[0-9A-Fa-f]{2})*)@)?((?:\\[(?:(?:(?:(?:[0-9A-Fa-f]{1,4}:){6}|::(?:[0-9A-Fa-f]{1,4}:){5}|(?:[0-9A-Fa-f]{1,4})?::(?:[0-9A-Fa-f]{1,4}:){4}|(?:(?:[0-9A-Fa-f]{1,4}:){0,1}[0-9A-Fa-f]{1,4})?::(?:[0-9A-Fa-f]{1,4}:){3}|(?:(?:[0-9A-Fa-f]{1,4}:){0,2}[0-9A-Fa-f]{1,4})?::(?:[0-9A-Fa-f]{1,4}:){2}|(?:(?:[0-9A-Fa-f]{1,4}:){0,3}[0-9A-Fa-f]{1,4})?::[0-9A-Fa-f]{1,4}:|(?:(?:[0-9A-Fa-f]{1,4}:){0,4}[0-9A-Fa-f]{1,4})?::)(?:[0-9A-Fa-f]{1,4}:[0-9A-Fa-f]{1,4}|(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))|(?:(?:[0-9A-Fa-f]{1,4}:){0,5}[0-9A-Fa-f]{1,4})?::[0-9A-Fa-f]{1,4}|(?:(?:[0-9A-Fa-f]{1,4}:){0,6}[0-9A-Fa-f]{1,4})?::)|[Vv][0-9A-Fa-f]+\\.[A-Za-z0-9\\-._~!$&'()*+,;=:]+)\\]|(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)|(?:[A-Za-z0-9\\-._~!$&'()*+,;=]|%[0-9A-Fa-f]{2})*))(?::([0-9]*))?((?:/(?:[A-Za-z0-9\\-._~!$&'()*+,;=:@]|%[0-9A-Fa-f]{2})*)*)|/((?:(?:[A-Za-z0-9\\-._~!$&'()*+,;=:@]|%[0-9A-Fa-f]{2})+(?:/(?:[A-Za-z0-9\\-._~!$&'()*+,;=:@]|%[0-9A-Fa-f]{2})*)*)?)|((?:[A-Za-z0-9\\-._~!$&'()*+,;=:@]|%[0-9A-Fa-f]{2})+(?:/(?:[A-Za-z0-9\\-._~!$&'()*+,;=:@]|%[0-9A-Fa-f]{2})*)*)|)(?:\\?((?:[A-Za-z0-9\\-._~!$&'()*+,;=:@/?]|%[0-9A-Fa-f]{2})*))?(?:\\#((?:[A-Za-z0-9\\-._~!$&'()*+,;=:@/?]|%[0-9A-Fa-f]{2})*))?"
}
```

> **Example Matches:**
>
> ```
> http://foo.bar
> https://foo.bar
> http://foo.bar/baz
> https://foo.bar/baz
> http://foo.bar:3000
> http://foo.bar:3000/baz
> git://foo.bar/baz
> ssh://git@foo.bar/baz
> ssh://git@foo.bar/baz.git
> ```

### `uuid`

```javascript
{
  "id": "types.uuid",
  "type": "string",
  "format": "uuid",
  "pattern": "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[34][0-9a-fA-F]{3}-[89ab][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$"
}
```

> **Example Matches:**
>
> ```
> efbf1234-1242-3fd1-8d9c-94d8c3a22ec7
> 14f114e8-449b-4bb8-b6b6-e0fe48b650e5
> 39b88796-8b6b-4f76-aacd-a530235f85b8
> 623bf773-a86f-4371-81c6-b4133cc67c73
> 69dab668-bcb6-40f9-90b2-0d3181da0987
> 9f20d246-bc75-4a8b-b423-9a238a7ea151
> 756be421-8985-4c0b-adc8-3c65c5807622
> ff984090-387d-4cc8-b9f9-1f4e348a9170
> 944595f4-8748-4ae7-bd4c-4de44e1cc2b3
> ff5d5b00-dc27-4ea7-a19f-8f934cee64f8
> 3fab55f4-a235-479c-8d79-60eba475390f
> 72308901-0849-4fb3-89a7-5e332672e785
> a8ab4e37-9786-46a3-955b-7c4fd5ed4f70
> ```


---

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```
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