JSPM – @tpluscode/rdfine@0.2.2

Package Exports

@tpluscode/rdfine

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@tpluscode/rdfine) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

RDFine /rɪdɪˈfaɪn/

RDF/JS idiomatic, native, enjoyable

Installation

npm i @tplusode/rdfine

Also peer @types dependencies:

npm i --save-dev @types/clownface @types/rdf-ext @types/rdfjs__namespace

Usage

Define resource interfaces

While it is possible to inherit a base resource class, it's best to create partial mixin classes which implement part of the RDF model. Mixins are dynamically applied to compose a JavaScript object model closely matching the actual quad data.

// Person.ts
import { Constructor, namespace, property, RdfResource } from '@tplusode/rdfine'
import { Term } from 'rdf-js'
import { namedNode } from 'rdf-data-model'

// TS: define an interface for your object model
export interface Person extends RdfResource {
  name: string
  friends: Person[]
}

export function PersonMixin<Base extends Constructor>(base: Base) {
  @namespace('http://schema.org/')
  class P extends base implements Person {
  
    // Literal property
    // By default use the property's name with the annotated @namespace    
    @property.literal()
    name!: string  // http://schema.org/name

    // Customize the getter to return objects of a certain property
    @property.resource({
      // http://schema.org/knows
      path: 'knows',
      // always return a JS array
      values: 'array'
    })
    friends!: Person[]
    
    // getting raw RDF/JS terms
    // by annotating with plain @property
    @property({ 
      path: 'http://www.w3.org/2000/01/rdf-schema#label'
    })
    label: Term
    
    // use _node property to access raw triples
    // by traversing the graph with https://github.com/rdf-ext/clownface
    get hasOccupation(): boolean {
      return this._node
        .out(namedNode('http://schema.org/hasOccupation'))
        .terms.length > 0
    }
  }
 
  return P
}

// add a function to decide if the underlying resource
// satisfies the Person interface
// for example by checking its RDF types
PersonMixin.shouldApply = (res: RdfResource) => {
  return res.hasType('http://schema.org/Person')
}

Creating resource instances

Instead of directly creating resource types, which would require deciding up-front, which mixins to add to the constructed class, a factory can be used.

import { DatasetCore } from 'rdf-js'
import { namedNode } from 'rdf-data-model'
import { RdfResourceImpl } from '@tpluscode/rdfine'
import { Person, PersonMixin } from './Person'

// register the mixin type with the factory
factory.addMixin(PersonMixin)

// load you RDF triples into a RDF/JS dataset
let dataset: DatasetCore = loadRdfData()

const person = RdfResourceImpl.factory.createEntity<Person>({
  dataset,
  term: namedNode('http://example.com/gh/tpluscode')
})

Use it!

The setters are immediately reflected in the underlying dataset. Note that any property can also be set with raw RDF term matching the annotated type

import { namedNode } from 'rdf-data-model'

person.name = "Tomasz"
person.friends = [
  namedNode('http://example.com/gh/bergos'),
  namedNode('http://example.com/gh/ktk')
] as any

console.log(person._node.dataset.toString())

The last line above will print triples equivalent to those below

@prefix schema: <http://schema.org/> .

<http://example.com/gh/tpluscode> 
    schema:name "Tomasz" ;
    schema:knows <http://example.com/gh/bergos> , <http://example.com/gh/ktk>  .

Using with babel

npm i -D @babel/preset-env @babel/plugin-proposal-decorators @babel/plugin-proposal-class-properties

Configure babel (for example with .babelrc)

{
  "presets": [
    [
      "@babel/env"
  ],
  "plugins": [
    [
      "@babel/plugin-proposal-decorators",
      {
        "decoratorsBeforeExport": true
      }
    ],
    [
      "@babel/proposal-class-properties"
    ]
  ]
}