Siren.js Core

Cross-platform library of classes for generating and parsing Siren entities.

Table of Contents

• Table of Contents
• Install
• Usage
  • Creating an Entity
  • Generating an Entity
  • Parsing Siren
  • Querying an Entity
  • Querying an Action
  • Extensions
• Contributing
• License

Install

npm install @siren-js/core

Usage

Creating an Entity

Here's a simple example of generating an entity:

import * as Siren from '@siren-js/core';

const person = Siren.Entity.of({
  class: ['Person'],
  properties: {
    givenName: 'Neville',
    familyName: 'Longbottom',
    birthDate: '1980-07-30'
  },
  links: [
    {
      rel: ['self'],
      href: 'https://api.example.com/people/69'
    }
  ]
});

Here is a more complete example building out the order entity example from the Siren spec:

const order = {
  orderNumber: 42,
  itemCount: 3,
  status: 'pending',
  customer: {
    userId: 'pj123',
    name: 'Peter Joseph'
  }
};

const orderEntity = Siren.Entity.of({
  class: ['order'],
  properties: {
    orderNumber: order.orderNumber,
    itemCount: order.itemCount,
    status: order.status
  },
  entities: [
    {
      class: ['items', 'collection'],
      rel: ['http://x.io/rels/order-items'],
      href: `http://api.x.io/orders/${order.orderNumber}/items`
    },
    {
      class: ['info', 'customer'],
      rel: ['http://x.io/rels/customer'],
      properties: {
        customerId: order.customer.userId,
        name: order.customer.name
      },
      links: [
        {
          rel: ['self'],
          href: `http://api.x.io/customers/${order.customer.userId}`
        }
      ]
    }
  ],
  actions: [
    {
      name: 'add-item',
      title: 'Add Item',
      method: 'POST',
      href: `http://api.x.io/orders/${order.orderNumber}/items`,
      type: 'application/x-www-form-urlencoded',
      fields: [
        { name: 'orderNumber', type: 'hidden', value: `${order.orderNumber}` },
        { name: 'productCode', type: 'text' },
        { name: 'quantity', type: 'number' }
      ]
    }
  ],
  links: [
    {
      rel: ['self'],
      href: `http://api.x.io/orders/${order.orderNumber}`
    },
    {
      rel: ['previous'],
      href: `http://api.x.io/orders/${order.orderNumber - 1}`
    },
    {
      rel: ['next'],
      href: `http://api.x.io/orders/${order.orderNumber + 1}`
    }
  ]
});

Generating an Entity

Use the stringify function to convert an Entity into Siren JSON (application/vnd.siren+json).

const siren = Siren.stringify(person);
// => "{ "class": ["Person"], ... }"

Parsing Siren

Use the parse function to convert a Siren JSON string to an Entity.

const entity = Siren.parse(siren);
// `entity` is equivalent to `person`

Querying an Entity

The Entity class provides several convenience methods for finding actions or links within the entity:

const addItemAction = orderEntity.findActionByName('add-item');
const customerSubEntities = orderEntity.findEntitiesByRel('customer');
const nextOrderLinks = orderEntity.findLinksByRel('next');

Querying an Action

The Action class also provides convenience methods for finding fields:

const productCodeField = addItemAction.findFieldByName('productCode');

Extensions

Extensions are supported for every type of object. Here's an example using min and max constraints for a Field and hreflang for a Link:

Siren.Entity.of({
  actions: [
    {
      name: 'guess-number',
      href: 'https://api.example.com/guess',
      fields: [
        {
          name: 'guess',
          type: 'number',
          min: 0,
          max: 100
        }
      ]
    }
  ]
  links: [
    {
      rel: ['about'],
      href: 'https://api.example.com/about',
      hreflang: 'en-US'
    }
  ]
});

Contributing

PRs and bug reports welcome! Be sure to read our contribution guidelines.

License

MIT © Siren.js