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    jsonldpublic

    jsonld.js

    Build status Dependency Status

    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 dereferencable 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 pass the test suite and conform with the following:

    Installation

    node.js + npm

    npm install jsonld
    
    const jsonld = require('jsonld');

    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

    var 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"}
    };
    var context = {
      "name": "http://schema.org/name",
      "homepage": {"@id": "http://schema.org/url", "@type": "@id"},
      "image": {"@id": "http://schema.org/image", "@type": "@id"}
    };
     
    // compact a document according to a particular context
    // see: http://json-ld.org/spec/latest/json-ld/#compacted-document-form
    jsonld.compact(doc, context, function(err, compacted) {
      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
    jsonld.compact('http://example.org/doc', 'http://example.org/context', ...);
     
    // expand a document, removing its context
    // see: http://json-ld.org/spec/latest/json-ld/#expanded-document-form
    jsonld.expand(compacted, function(err, expanded) {
      /* 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
    jsonld.expand('http://example.org/doc', ...);
     
    // flatten a document
    // see: http://json-ld.org/spec/latest/json-ld/#flattened-document-form
    jsonld.flatten(doc, (err, flattened) => {
      // all deep-level trees flattened to the top-level
    });
     
    // frame a document
    // see: http://json-ld.org/spec/latest/json-ld-framing/#introduction
    jsonld.frame(doc, frame, (err, framed) => {
      // document transformed into a particular tree structure per the given frame
    });
     
    // canonize (normalize) a document using the RDF Dataset Normalization Algorithm
    // (URDNA2015), see: http://json-ld.github.io/normalization/spec/
    jsonld.canonize(doc, {
      algorithm: 'URDNA2015',
      format: 'application/n-quads'
    }, (err, canonized) => {
      // canonized is a string that is a canonical representation of the document
      // that can be used for hashing, comparison, etc.
    });
     
    // serialize a document to N-Quads (RDF)
    jsonld.toRDF(doc, {format: 'application/n-quads'}, (err, nquads) => {
      // nquads is a string of N-Quads
    });
     
    // deserialize N-Quads (RDF) to JSON-LD
    jsonld.fromRDF(nquads, {format: 'application/n-quads'}, (err, doc) => {
      // doc is JSON-LD
    });
     
    // register a custom async-callback-based RDF parser
    jsonld.registerRDFParser(contentType, (input, callback) => {
      // parse input to a jsonld.js RDF dataset object...
      callback(err, dataset);
    });
     
    // register a custom synchronous RDF parser
    jsonld.registerRDFParser(contentType, input => {
      // parse input to a jsonld.js RDF dataset object... and return it
      return dataset;
    });
     
    // use the promises API:
     
    // compaction
    const compacted = await jsonld.compact(doc, context);
     
    // expansion
    const expanded = await jsonld.expand(doc);
     
    // flattening
    const flattened = await jsonld.flatten(doc);
     
    // framing
    const framed = await jsonld.frame(doc, frame);
     
    // canonicalization (normalization)
    const canonized = await jsonld.canonize(doc, {format: 'application/n-quads'});
     
    // serialize to RDF
    const rdf = await jsonld.toRDF(doc, {format: 'application/n-quads'});
     
    // deserialize from RDF
    const doc = await jsonld.fromRDF(nquads, {format: 'application/n-quads'});
     
    // register a custom promise-based RDF parser
    jsonld.registerRDFParser(contentType, async input => {
      // parse input into a jsonld.js RDF dataset object...
      return new Promise(...);
    });
     
    // 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 using the callback API
    // (you can also do this using the promise-based API, return a promise instead
    // of using a callback)
    const customLoader = (url, callback) => {
      if(url in CONTEXTS) {
        return callback(
          null, {
            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 underlining documentLoader using the callback API.
      nodeDocumentLoader(url, callback);
      /* Note: By default, the node.js document loader uses a callback, but
      browser-based document loaders (xhr or jquery) return promises if they
      are supported (or polyfilled) in the browser. This behavior can be
      controlled with the 'usePromise' option when constructing the document
      loader. For example: jsonld.documentLoaders.xhr({usePromise: false}); */
    };
    jsonld.documentLoader = customLoader;
     
    // alternatively, pass the custom loader for just a specific call:
    const compacted = await jsonld.compact(
    doc, context, {documentLoader: customLoader});

    Related Modules

    • jsonld-cli: A command line interface tool called jsonld that exposes most of the basic jsonld.js API.
    • jsonld-request: A module that can read data from stdin, URLs, and files and in various formats and return JSON-LD.

    Commercial Support

    Commercial support for this library is available upon request from Digital Bazaar: support@digitalbazaar.com

    Source

    The source code for the JavaScript implementation of the JSON-LD API is available at:

    http://github.com/digitalbazaar/jsonld.js

    Tests

    This library includes a sample testing utility which may be used to verify that changes to the processor maintain the correct output.

    The main test suites are included in external repositories. Check out each of the following:

    https://github.com/json-ld/json-ld.org
    https://github.com/json-ld/normalization
    

    They should be sibling directories of the jsonld.js directory or in a test-suites dir. To clone shallow copies into the test-suites dir you can use the following:

    npm run fetch-test-suites
    

    Node.js tests can be run with a simple command:

    npm test
    

    If you installed the test suites elsewhere, or wish to run other tests, use the JSONLD_TESTS environment var:

    JSONLD_TESTS="/tmp/org/test-suites /tmp/norm/tests" npm test
    

    Browser testing can be done with Karma:

    npm test-karma
    npm test-karma -- --browsers Firefox,Chrome
    

    Code coverage of node tests can be generated in coverage/:

    npm run coverage
    

    To display a full coverage report on the console from coverage data:

    npm run coverage-report
    

    The Mocha output reporter can be changed to min, dot, list, nyan, etc:

    REPORTER=dot npm test
    

    Remote context tests are also available:

    # run the context server in the background or another terminal
    node tests/remote-context-server.js
    
    JSONLD_TESTS=./tests npm test
    

    To generate earl reports:

    # generate the earl report for node.js
    EARL=earl-node.jsonld npm test
    
    # generate the earl report for the browser
    EARL=earl-firefox.jsonld npm test-karma -- --browser Firefox
    

    install

    npm i jsonld

    Downloadsweekly downloads

    3,465

    version

    1.0.1

    license

    BSD-3-Clause

    repository

    githubgithub

    last publish

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