# JSON Schema $Ref Parser
_**This package needs [a new maintainer](https://github.com/APIDevTools/json-schema-ref-parser/issues/285) or at least some contributors. For more information [please read this article](https://phil.tech/2022/bundling-openapi-with-javascript/). 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](https://protect.earth/) 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](https://github.com/philsturgeon)_
#### Parse, Resolve, and Dereference JSON Schema $ref pointers
[](https://github.com/APIDevTools/json-schema-ref-parser/actions)
[](https://coveralls.io/github/APIDevTools/json-schema-ref-parser)
[](https://www.npmjs.com/package/@apidevtools/json-schema-ref-parser)
[](LICENSE)
[](https://plant.treeware.earth/APIDevTools/json-schema-ref-parser)
The Problem:
--------------------------
You've got a JSON Schema with `$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.
```javascript
{
"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 $Ref Parser is a full [JSON Reference](https://tools.ietf.org/html/draft-pbryan-zyp-json-ref-03) and [JSON Pointer](https://tools.ietf.org/html/rfc6901) implementation that crawls even the most complex [JSON Schemas](http://json-schema.org/latest/json-schema-core.html) and gives you simple, straightforward JavaScript objects.
- Use **JSON** or **YAML** schemas — or even a mix of both!
- Supports `$ref` pointers to external files and URLs, as well as [custom sources](https://apitools.dev/json-schema-ref-parser/docs/plugins/resolvers.html) such as databases
- Can [bundle](https://apitools.dev/json-schema-ref-parser/docs/ref-parser.html#bundlepath-options-callback) multiple files into a single schema that only has _internal_ `$ref` pointers
- Can [dereference](https://apitools.dev/json-schema-ref-parser/docs/ref-parser.html#dereferencepath-options-callback) your schema, producing a plain-old JavaScript object that's easy to work with
- Supports [circular references](https://apitools.dev/json-schema-ref-parser/docs/#circular-refs), nested references, back-references, and cross-references between files
- Maintains object reference equality — `$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
--------------------------
```javascript
$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:
```javascript
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](https://apitools.dev/json-schema-ref-parser/docs/)
Installation
--------------------------
Install using [npm](https://docs.npmjs.com/about-npm/):
```bash
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:
```javascript
const $RefParser = require("@apidevtools/json-schema-ref-parser");
```
When using a transpiler such as [Babel](https://babeljs.io/) or [TypeScript](https://www.typescriptlang.org/), or a bundler such as [Webpack](https://webpack.js.org/) or [Rollup](https://rollupjs.org/), you can use **ECMAScript modules** syntax instead:
```javascript
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](https://github.com/node-fetch/node-fetch):
```javascript
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](https://babeljs.io/) and/or [polyfills](https://babeljs.io/docs/en/next/babel-polyfill).
To use JSON Schema $Ref Parser in a browser, you'll need to use a bundling tool such as [Webpack](https://webpack.js.org/), [Rollup](https://rollupjs.org/), [Parcel](https://parceljs.org/), or [Browserify](http://browserify.org/). Some bundlers may require a bit of configuration, such as setting `browser: true` in [rollup-plugin-resolve](https://github.com/rollup/rollup-plugin-node-resolve).
API Documentation
--------------------------
Full API documentation is available [right here](https://apitools.dev/json-schema-ref-parser/docs/)
Contributing
--------------------------
I welcome any contributions, enhancements, and bug-fixes. [Open an issue](https://github.com/APIDevTools/json-schema-ref-parser/issues) on GitHub and [submit a pull request](https://github.com/APIDevTools/json-schema-ref-parser/pulls).
#### Building/Testing
To build/test the project locally on your computer:
1. __Clone this repo__<br>
`git clone https://github.com/APIDevTools/json-schema-ref-parser.git`
2. __Install dependencies__<br>
`npm install`
3. __Run the tests__<br>
`npm test`
License
--------------------------
JSON Schema $Ref Parser is 100% free and open-source, under the [MIT license](LICENSE). Use it however you want.
This package is [Treeware](http://treeware.earth). If you use it in production, then we ask that you [**buy the world a tree**](https://plant.treeware.earth/APIDevTools/json-schema-ref-parser) 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 ❤
[](https://stoplight.io/?utm_source=github&utm_medium=readme&utm_campaign=json_schema_ref_parser)
[](https://saucelabs.com)
[](https://coveralls.io)
![[ICO]](/icons/blank.gif){kind=icon}
![[PARENTDIR]](/icons/back.gif){kind=icon}
![[DIR]](/icons/folder.gif){kind=icon}
![[ ]](/icons/unknown.gif){kind=icon}
![[TXT]](/icons/text.gif){kind=icon}