JSON Schema $Ref Parser

Parse, Resolve, and Dereference JSON Schema $ref pointers

The Problem:

You've got a JSON Schema with $ref pointers to other files and/or URLs. Maybe you know all the referenced files ahead of time. Maybe you don't. Maybe some are local files, and others are remote URLs. Maybe they are a mix of JSON and YAML format. Maybe some of the files contain cross-references to each other.

{
  "definitions": {
    "person": {
      // references an external file
      "$ref": "schemas/people/Bruce-Wayne.json"
    },
    "place": {
      // references a sub-schema in an external file
      "$ref": "schemas/places.yaml#/definitions/Gotham-City"
    },
    "thing": {
      // references a URL
      "$ref": "http://wayne-enterprises.com/things/batmobile"
    },
    "color": {
      // references a value in an external file via an internal reference
      "$ref": "#/definitions/thing/properties/colors/black-as-the-night"
    }
  }
}

The Solution:

JSON Schema $Ref Parser is a full JSON Reference and JSON Pointer implementation that crawls even the most complex JSON Schemas and gives you simple, straightforward JavaScript objects.

• Use JSON or YAML schemas — or even a mix of both!
• Supports $ref pointers to external files and URLs, as well as custom sources such as databases
• Can bundle multiple files into a single schema that only has internal $ref pointers
• Can dereference your schema, producing a plain-old JavaScript object that's easy to work with
• Supports circular references, nested references, back-references, and cross-references between files
• Maintains object reference equality — $ref pointers to the same value always resolve to the same object instance
• Tested in Node, io.js, and all major web browsers on Windows, Mac, and Linux

Example

$RefParser.dereference(mySchema, function(err, schema) {
  if (err) {
    console.error(err);
  }
  else {
    // `schema` is just a normal JavaScript object that contains your entire JSON Schema,
    // including referenced files, combined into a single object
    console.log(schema.definitions.person.properties.firstName);
  }
});

Or use Promises syntax instead. The following example is the same as above:

$RefParser.dereference(mySchema)
  .then(function(schema) {
    console.log(schema.definitions.person.properties.firstName);
  })
  .catch(function(err) {
    console.error(err);
  });

For more detailed examples, please see the API Documentation

Installation

Node

Install using npm:

npm install json-schema-ref-parser

Then require it in your code:

var $RefParser = require('json-schema-ref-parser');

Web Browsers

Install using bower:

bower install json-schema-ref-parser

Then reference ref-parser.js or ref-parser.min.js in your HTML:

<script src="bower_components/json-schema-ref-parser/dist/ref-parser.js"></script>

Or, if you're using AMD (Require.js), then import it into your module:

define(["ref-parser"], function($RefParser) { /* your module's code */ })

API Documentation

Full API documentation is available right here

Contributing

I welcome any contributions, enhancements, and bug-fixes. File an issue on GitHub and submit a pull request.

Building/Testing

To build/test the project locally on your computer:

1. Clone this repo
   git clone https://github.com/bigstickcarpet/json-schema-ref-parser.git

2. Install dependencies
   npm install

3. Run the build script
   npm run build

4. Run the unit tests
   npm run mocha (test in Node)
   npm run karma (test in web browsers)
   npm test (test in Node and browsers, and report code coverage)

5. Start the local web server
   npm start (then browse to http://localhost:8080/test/index.html)

License

JSON Schema $Ref Parser is 100% free and open-source, under the MIT license. Use it however you want.