jsonld.js

Introduction

This library is an implementation of the [JSON-LD][] specification in JavaScript.

JSON, as specified in [RFC7159][], is a simple language for representing objects on the Web. Linked Data is a way of describing content across different documents or Web sites. Web resources are described using IRIs, and typically are dereferenceable entities that may be used to find more information, creating a "Web of Knowledge". [JSON-LD][] is intended to be a simple publishing method for expressing not only Linked Data in JSON, but for adding semantics to existing JSON.

JSON-LD is designed as a light-weight syntax that can be used to express Linked Data. It is primarily intended to be a way to express Linked Data in JavaScript and other Web-based programming environments. It is also useful when building interoperable Web Services and when storing Linked Data in JSON-based document storage engines. It is practical and designed to be as simple as possible, utilizing the large number of JSON parsers and existing code that is in use today. It is designed to be able to express key-value pairs, RDF data, [RDFa][] data, [Microformats][] data, and [Microdata][]. That is, it supports every major Web-based structured data model in use today.

The syntax does not require many applications to change their JSON, but easily add meaning by adding context in a way that is either in-band or out-of-band. The syntax is designed to not disturb already deployed systems running on JSON, but provide a smooth migration path from JSON to JSON with added semantics. Finally, the format is intended to be fast to parse, fast to generate, stream-based and document-based processing compatible, and require a very small memory footprint in order to operate.

Conformance

This library aims to conform with the following:

[JSON-LD 1.0][], W3C Recommendation, 2014-01-16, and any [errata][]
[JSON-LD 1.0 Processing Algorithms and API][JSON-LD 1.0 API], W3C Recommendation, 2014-01-16, and any [errata][]
[JSON-LD 1.0 Framing][JSON-LD 1.0 Framing], Unofficial Draft, 2012-08-30
[JSON-LD 1.1][JSON-LD CG 1.1], Draft Community Group Report, 2018-06-07 or [newer][JSON-LD CG latest]
[JSON-LD 1.1 Processing Algorithms and API][JSON-LD CG 1.1 API], Draft Community Group Report, 2018-06-07 or [newer][JSON-LD CG API latest]
[JSON-LD 1.1 Framing][JSON-LD CG 1.1 Framing], Draft Community Group Report, 2018-06-07 or [newer][JSON-LD CG Framing latest]
Community Group [test suite][]

The [JSON-LD Working Group][JSON-LD WG] is now developing JSON-LD 1.1. Library updates to conform with newer specifications will happen as features stabilize and development time and resources permit.

[JSON-LD 1.1][JSON-LD WG 1.1], W3C Working Draft, 2018-12-14 or [newer][JSON-LD WG latest]
[JSON-LD 1.1 Processing Algorithms and API][JSON-LD WG 1.1 API], W3C Working Draft, 2018-12-14 or [newer][JSON-LD WG API latest]
[JSON-LD 1.1 Framing][JSON-LD WG 1.1 Framing], W3C Working Draft, 2018-12-14 or [newer][JSON-LD WG Framing latest]
Working Group [test suite][WG test suite]

The [test runner][] is often updated to note or skip newer tests that are not yet supported.

Installation

Node.js + npm

npm install jsonld

const jsonld = require('jsonld');

import jsonld from 'jsonld';

Browser (bundler) + npm

npm install jsonld

Use your favorite bundling technology ([webpack][], [Rollup][], etc) to directly bundle your code that loads jsonld. Note that you will need support for ES2017+ code.

Browser Bundles

The built npm package includes bundled code suitable for use in browsers. Two versions are provided:

./dist/jsonld.min.js: A version built for wide compatibility with modern and older browsers. Includes many polyfills and code transformations and is larger and less efficient.
./dist/jsonld.esm.min.js: A version built for features available in browsers that support ES Modules. Fewer polyfills and transformations are required making the code smaller and more efficient.

The two bundles can be used at the same to to allow modern browsers to use newer code. Lookup using script tags with type="module" and nomodule.

Also see the webpack.config.js if you would like to make a custom bundle for specific targets.

Browser (AMD) + npm

npm install jsonld

Use your favorite technology to load node_modules/dist/jsonld.min.js.

CDNJS CDN

To use CDNJS include this script tag:

<script src="https://cdnjs.cloudflare.com/ajax/libs/jsonld/1.0.0/jsonld.min.js"></script>

Check https://cdnjs.com/libraries/jsonld for the latest available version.

jsDeliver CDN

To use jsDeliver include this script tag:

<script src="https://cdn.jsdelivr.net/npm/jsonld@1.0.0/dist/jsonld.min.js"></script>

See https://www.jsdelivr.com/package/npm/jsonld for the latest available version.

unpkg CDN

To use unpkg include this script tag:


<script src="https://unpkg.com/jsonld@1.0.0/dist/jsonld.min.js"></script>

See https://unpkg.com/jsonld/ for the latest available version.

JSPM

jspm install npm:jsonld

import * as jsonld from 'jsonld';
// or
import {promises} from 'jsonld';
// or
import {JsonLdProcessor} from 'jsonld';

Examples

Example data and context used throughout examples below:

const doc = {
  "http://schema.org/name": "Manu Sporny",
  "http://schema.org/url": {"@id": "http://manu.sporny.org/"},
  "http://schema.org/image": {"@id": "http://manu.sporny.org/images/manu.png"}
};
const context = {
  "name": "http://schema.org/name",
  "homepage": {"@id": "http://schema.org/url", "@type": "@id"},
  "image": {"@id": "http://schema.org/image", "@type": "@id"}
};

compact

// compact a document according to a particular context
const compacted = await jsonld.compact(doc, context);
console.log(JSON.stringify(compacted, null, 2));
/* Output:
{
  "@context": {...},
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "image": "http://manu.sporny.org/images/manu.png"
}
*/

// compact using URLs
const compacted = await jsonld.compact(
  'http://example.org/doc', 'http://example.org/context', ...);

expand

// expand a document, removing its context
const expanded = await jsonld.expand(compacted);
/* Output:
{
  "http://schema.org/name": [{"@value": "Manu Sporny"}],
  "http://schema.org/url": [{"@id": "http://manu.sporny.org/"}],
  "http://schema.org/image": [{"@id": "http://manu.sporny.org/images/manu.png"}]
}
*/

// expand using URLs
const expanded = await jsonld.expand('http://example.org/doc', ...);

flatten

// flatten a document
const flattened = await jsonld.flatten(doc);
// output has all deep-level trees flattened to the top-level

frame

// frame a document
const framed = await jsonld.frame(doc, frame);
// output transformed into a particular tree structure per the given frame

<a name="canonize"></a>canonize (normalize)

// canonize (normalize) a document using the RDF Dataset Canonicalization Algorithm
// (URDNA2015):
const canonized = await jsonld.canonize(doc, {
  algorithm: 'URDNA2015',
  format: 'application/n-quads'
});
// canonized is a string that is a canonical representation of the document
// that can be used for hashing, comparison, etc.

<a name="tordf"></a>toRDF (N-Quads)

// serialize a document to N-Quads (RDF)
const nquads = await jsonld.toRDF(doc, {format: 'application/n-quads'});
// nquads is a string of N-Quads

<a name="fromrdf"></a>fromRDF (N-Quads)

// deserialize N-Quads (RDF) to JSON-LD
const doc = await jsonld.fromRDF(nquads, {format: 'application/n-quads'});
// doc is JSON-LD

Custom RDF Parser

// register a custom synchronous RDF parser
jsonld.registerRDFParser(contentType, input => {
  // parse input to a jsonld.js RDF dataset object... and return it
  return dataset;
});

// register a custom promise-based RDF parser
jsonld.registerRDFParser(contentType, async input => {
  // parse input into a jsonld.js RDF dataset object...
  return new Promise(...);
});

Custom Document Loader

// how to override the default document loader with a custom one -- for
// example, one that uses pre-loaded contexts:

// define a mapping of context URL => context doc
const CONTEXTS = {
  "http://example.com": {
    "@context": ...
  }, ...
};

// grab the built-in Node.js doc loader
const nodeDocumentLoader = jsonld.documentLoaders.node();
// or grab the XHR one: jsonld.documentLoaders.xhr()

// change the default document loader
const customLoader = async (url, options) => {
  if(url in CONTEXTS) {
    return {
      contextUrl: null, // this is for a context via a link header
      document: CONTEXTS[url], // this is the actual document that was loaded
      documentUrl: url // this is the actual context URL after redirects
    };
  }
  // call the default documentLoader
  return nodeDocumentLoader(url);
};
jsonld.documentLoader = customLoader;

// alternatively, pass the custom loader for just a specific call:
const compact

Jsonld.js

Install / Use

README