README
@rdfjs/serializer-jsonld-ext
JSON-LD serializer that implements the RDFJS Sink interface and supports different output styles. This package handles the stream processing and uses jsonld.js for the actual serialization process.
Usage
The package exports the serializer as a class, so an instance must be created before it can be used.
The .import
method, as defined in the RDFJS specification, must be called to do the actual serialization.
It expects a quad stream as argument.
The method will return a stream which emits the JSON-LD as a plain object or string.
The constructor accepts an options
object with the following optional keys:
context
: JSON-LD context that will be used for compact, flatten or frame. The context must be given as a plain object. By default{}
is used.compact
: If this flag istrue
, the jsonld.js compact will be used to process the output.flatten
: If this flag istrue
, the jsonld.js flatten will be used to process the output.frame
: If this flag istrue
, the jsonld.js frame will be used to process the output.skipContext
: Removes the@context
property from the output. Useful for HTTP server when the media typeapplication/json
is used and a context is provided as header link.encoding
: Defines the encoding of the output. Supported encodings arestring
andobject
. By defaultobject
is used.
It's also possible to pass options as second argument to the .import
method.
The options from the constructor and the .import
method will be merged together.
Example
This example shows how to create a serializer instance and how to feed it with a stream of quads.
The output will be processed with compact
using the given context.
The object emitted by the serializer will be written to the console.
const rdf = require('@rdfjs/data-model')
const Readable = require('stream').Readable
const SerializerJsonld = require('@rdfjs/serializer-jsonld-ext')
const context = {
'@vocab': 'http://schema.org/',
ex: 'http://example.org/'
}
const serializerJsonld = new SerializerJsonld({ context, compact: true })
const input = new Readable({
objectMode: true,
read: () => {
input.push(rdf.quad(
rdf.namedNode('http://example.org/sheldon-cooper'),
rdf.namedNode('http://schema.org/givenName'),
rdf.literal('Sheldon')))
input.push(rdf.quad(
rdf.namedNode('http://example.org/sheldon-cooper'),
rdf.namedNode('http://schema.org/familyName'),
rdf.literal('Cooper')))
input.push(rdf.quad(
rdf.namedNode('http://example.org/sheldon-cooper'),
rdf.namedNode('http://schema.org/knows'),
rdf.namedNode('http://example.org/amy-farrah-fowler')))
input.push(null)
}
})
const output = serializerJsonld.import(input)
output.on('data', jsonld => {
console.log(jsonld)
})
// output:
// {
// '@context': { '@vocab': 'http://schema.org/', ex: 'http://example.org/' },
// '@id': 'ex:sheldon-cooper',
// familyName: 'Cooper',
// givenName: 'Sheldon',
// knows: { '@id': 'ex:amy-farrah-fowler' }
// }