@bcherny/json-schema-ref-parser

What is @bcherny/json-schema-ref-parser?

@bcherny/json-schema-ref-parser is a powerful library for parsing, resolving, and dereferencing JSON Schema $ref pointers. It helps in handling complex JSON schemas with references to other schemas, either local or remote.

What are @bcherny/json-schema-ref-parser's main functionalities?

Dereferencing

Dereferencing resolves all $ref pointers in the schema, replacing them with the actual referenced values. This is useful for working with a fully resolved schema.

const $RefParser = require('@bcherny/json-schema-ref-parser');

const schema = {
  "$ref": "http://example.com/schema.json"
};

$RefParser.dereference(schema)
  .then(dereferencedSchema => {
    console.log(dereferencedSchema);
  })
  .catch(err => {
    console.error(err);
  });

Bundling

Bundling resolves all $ref pointers in the schema, but keeps the references intact. This is useful for creating a single schema file that contains all referenced schemas.

const $RefParser = require('@bcherny/json-schema-ref-parser');

const schema = {
  "$ref": "http://example.com/schema.json"
};

$RefParser.bundle(schema)
  .then(bundledSchema => {
    console.log(bundledSchema);
  })
  .catch(err => {
    console.error(err);
  });

Resolving

Resolving retrieves all referenced files and schemas, but does not dereference them. This is useful for understanding the structure and dependencies of a schema.

const $RefParser = require('@bcherny/json-schema-ref-parser');

const schema = {
  "$ref": "http://example.com/schema.json"
};

$RefParser.resolve(schema)
  .then(resolvedSchema => {
    console.log(resolvedSchema);
  })
  .catch(err => {
    console.error(err);
  });

Other packages similar to @bcherny/json-schema-ref-parser

json-schema-ref-parser

json-schema-ref-parser is another popular library for parsing, resolving, and dereferencing JSON Schema $ref pointers. It offers similar functionalities to @bcherny/json-schema-ref-parser, including dereferencing, bundling, and resolving schemas. The main difference is in the API design and some additional features like custom resolvers and parsers.

json-schema-deref-sync

json-schema-deref-sync is a synchronous alternative for dereferencing JSON Schema $ref pointers. It is useful when you need to resolve references in a blocking manner. However, it lacks some of the advanced features and flexibility of @bcherny/json-schema-ref-parser.

json-schema-ref-resolver

json-schema-ref-resolver is a lightweight library for resolving JSON Schema $ref pointers. It focuses on simplicity and ease of use, making it a good choice for smaller projects. However, it may not handle complex schemas as efficiently as @bcherny/json-schema-ref-parser.

README

JSON Schema $Ref Parser

This package needs a new maintainer or at least some contributors. For more information please read this article. As of v10.0.0 I am no longer spending any time working on this tool, so I can focus on scaling up my reforestation charity instead of burning myself out trying to maintain a whole load of OSS projects I don't use in my vanishingly small spare time. Get in touch if you'd like to take over. - Phil Sturgeon

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 v10, v12, & v14, and all major web browsers on Windows, Mac, and Linux

Example

$RefParser.dereference(mySchema, (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 async/await syntax instead. The following example is the same as above:

try {
  let schema = await $RefParser.dereference(mySchema);
  console.log(schema.definitions.person.properties.firstName);
}
catch(err) {
  console.error(err);
}

For more detailed examples, please see the API Documentation

Installation

Install using npm:

npm install @apidevtools/json-schema-ref-parser

Usage

When using JSON Schema $Ref Parser in Node.js apps, you'll probably want to use CommonJS syntax:

const $RefParser = require("@apidevtools/json-schema-ref-parser");

When using a transpiler such as Babel or TypeScript, or a bundler such as Webpack or Rollup, you can use ECMAScript modules syntax instead:

import $RefParser from "@apidevtools/json-schema-ref-parser";

If you are using Node.js < 18, you'll need a polyfill for fetch, like node-fetch:

import fetch from "node-fetch";

globalThis.fetch = fetch;

Browser support

JSON Schema $Ref Parser supports recent versions of every major web browser. Older browsers may require Babel and/or polyfills.

To use JSON Schema $Ref Parser in a browser, you'll need to use a bundling tool such as Webpack, Rollup, Parcel, or Browserify. Some bundlers may require a bit of configuration, such as setting browser: true in rollup-plugin-resolve.

API Documentation

Full API documentation is available right here

Contributing

I welcome any contributions, enhancements, and bug-fixes. Open 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/APIDevTools/json-schema-ref-parser.git

2. Install dependencies
   npm install

3. Run the tests
   npm test

License

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

This package is Treeware. If you use it in production, then we ask that you buy the world a tree to thank us for our work. By contributing to the Treeware forest you’ll be creating employment for local families and restoring wildlife habitats.

Big Thanks To

Thanks to these awesome companies for their support of Open Source developers ❤