Javascript implementation for COALA IP.

Install

This project is available through npm. To install run

> npm install coalaip --save

Linked Metadata

This project provides tools for structuring metadata, using schema definitions with the ability to set arbitrary properties on type instances. Metadata is translatable to linked-data formats (e.g. IPLD) for persistence to different databases/storage layers.

Module Overview

Core

This module contains the types outlined in the specification. Additional types have been included because types in the specification inherit from them or certain properties expect other types.

Music

This module extends the core module with the following types: MusicAlbum, MusicComposition, MusicGroup, MusicPlaylist, MusicRecording, and MusicRelease.

Getting Started

Some code to get started structuring metadata. In order to persist to a storage layer, consider using Constellate.

Create a Person

const Person = require('coalaip/lib/core').Person

const man = new Person()
man.setGivenName('John')
man.setFamilyName('Smith')
man.setEmail('[email protected]')
man.set('arbitrary', 'value')

// or if the object is already structured
const woman = {
  givenName: 'Jane',
  familyName: 'Smith',
  email: '[email protected]',
  arbitrary: 'value'
}

const person = new Person()
person.withData(woman)

Access the Person's data

console.log(man.data())

// {
//   "@context": "http://schema.org",
//   "@type": "Person",
//   "givenName": "John",
//   "familyName": "Smith",
//   "email": "[email protected]",
//   "arbitrary": "value"
// }

// or if you want the data canonically ordered...

console.log(man.dataOrdered())

// {
//   "@context": "http://schema.org",
//   "@type": "Person",
//   "arbitrary": "value",
//   "email": "[email protected]",
//   "familyName": "Smith",
//   "givenName": "John"
// }

Add/Set sub-instances

addProperty for property that expects an array

setProperty for property that expects a single value

const {
  MusicComposition,
  MusicGroup,
  MusicRecording
} = require('coalaip/lib/music')

// 'member' expects an array of Parties
const group = new MusicGroup()
group.setDescription('descriptive')
group.setName('Beatles')
group.addMember(man)
group.path = '<placeholder group path>'

const composition = new MusicComposition()
// 'composer' expects an array of Parties
composition.addComposer(man)
composition.path = '<placeholder composition path>'

const recording = new MusicRecording()
// 'byArtist' expects an array of MusicGroups
recording.addByArtist(group)
// 'recordingOf' expects a MusicComposition
recording.setRecordingOf(comp)

console.log(recording.data())

// {  
//   "@context": "http://coalaip.org",
//   "@type": "MusicRecording",
//   "byArtist": [  
//     {  
//       "@context": "http://schema.org",
//       "@type": "MusicGroup",
//       "name": "Beatles",
//       "description": "descriptive",
//       "member": [  
//         {  
//           "@context": "http://schema.org",
//           "@type": "Person",
//           "givenName": "John",
//           "familyName": "Smith",
//           "email": "[email protected]"
//         }
//       ]
//     }
//   ],
//   "recordingOf": {  
//     "@context": "http://coalaip.org",
//     "@type": "MusicComposition",
//     "composer": [  
//       {  
//         "@context": "http://schema.org",
//         "@type": "Person",
//         "givenName": "John",
//         "familyName": "Smith",
//         "email": "[email protected]"
//       }
//     ]
//   }
// }

// and the ipld...

console.log(recording.ipld())

// {  
//   "@context": "http://coalaip.org",
//   "@type": "MusicRecording",
//   "byArtist": [  
//     {  
//       "/": "<placeholder group path>"
//     }
//   ],
//   "recordingOf": {  
//     "/": "<placeholder composition path>"
//   }
// }

Access sub-instances

instance.subInstances() returns a flattened array with instance and the unique instances nested within instance. To ease handling of metadata in other programs, the instances are ordered based on the other instances they contain.

const metadata = recording.subInstances()
console.log(metadata)

// [man, group, composition, recording]

// (1) man contains no other instances
// (2,3) group and composition contain man
// (4) recording contains composition and group