Recursively resolve JSON pointers and remote authorities.
npm install @stoplight/json-ref-resolver
Follow $ref values in JSON Schema, OpenAPI (formerly known as Swagger), and any other objects with $ref values inside of them.
- View the changelog: Releases
- Performant: Hot paths are memoized, remote URIs are resolved concurrently, and the minimum surface area is crawled and resolved.
- Caching: Results from remote URIs are cached.
- Immutable: The original object is not changed, and structural sharing is used to only change relevant bits. example test
- Reference equality: $refs to the same location will resolve to the same object in memory. example test
- Flexible: Bring your own readers for http://, file://, mongo://, custom://... etc, or use [one of ours][json-ref-readers].
- Cross Platform: Supports POSIX and Windows style file paths.
- Reliable: Well tested to handle all sorts of circular reference edge cases.
Supported in modern browsers and node.
``bash`
yarn add @stoplight/json-ref-resolver
All relevant types and options can be found in src/types.ts.
`ts
// Import the Resolver class.
import { Resolver } from "@stoplight/json-ref-resolver";
/**
* Create a Resolver instance. Resolve can be called on this instance multiple times to take advantage of caching.
*
* @param globalOpts {IResolverOpts} [{}]
*
* These options are used on every resolve call for this resolver instance.
*
* See IResolverOpts interface defined in src/types.ts for available options.
*
* @return IResolver
*/
const resolver = new Resolver(globalOpts);
/**
* Resolve the passed in object, replacing all references.
* @param resolveOpts {any} - The object to resolve.
* @param resolveOpts {IResolveOpts} [{}]
*
* These options override any globalOpts specified on the resolver instance, and only apply during this resolve call.
*
* See IResolveOpts interface defined in src/types.ts for available options.`
*
* @return IResolveResult - see src/types.ts for interface definition.
*/
const resolved = await resolver.resolve(sourceObj, resolveOpts);
By default, only inline references will be dereferenced.
`ts
import { Resolver } from "@stoplight/json-ref-resolver";
const resolver = new Resolver();
const resolved = await resolver.resolve({
user: {
$ref: "#/models/user"
},
models: {
user: {
name: "john"
}
}
});
// ==> result is the original object, with local refs resolved and replaced
expect(resolved.result).toEqual({
user: {
name: "john"
},
models: {
user: {
name: "john"
}
}
});
`
This will dereference the minimal number of references needed for the given target, and return the target.
In the example below, the address reference (https://slow-website.com/definitions#/address) will NOT be dereferenced, since#/user
it is not needed to resolve the jsonPointer target we have specified. However, #/models/user/card IS dereferenced since#/user
it is needed in order to full dereference the property.
`ts
import { Resolver } from "@stoplight/json-ref-resolver";
const resolver = new Resolver();
const resolved = await resolver.resolve(
{
user: {
$ref: "#/models/user"
},
address: {
$ref: "https://slow-website.com/definitions#/address"
},
models: {
user: {
name: "john",
card: {
$ref: "#/models/card"
}
},
card: {
type: "visa"
}
}
},
{
jsonPointer: "#/user"
}
);
// ==> result is the target object, with refs resolved and replaced
expect(resolved.result).toEqual({
name: "john",
card: {
type: "visa"
}
});
`
By default only inline references (those that point to values inside of the original object) are dereferenced.
In order to dereference remote URIs (file, http, etc) you must provide resolvers for each URI scheme.
Resolvers are keyed by scheme, receive the URI to fetch, and must return the fetched data.
`ts
import { Resolver } from "@stoplight/json-ref-resolver";
// some example http library
import * as axios from "axios";
// if we're in node, we create a file resolver with fs
import * as fs from "fs";
// create our resolver instance
const resolver = new Resolver({
// resolvers can do anything, so long as they define an async read function that resolves to a value
resolvers: {
// this resolver will be invoked for refs with the https protocol
https: {
async resolve(ref: uri.URI) {
return axios({
method: "get",
url: String(ref)
});
}
},
// this resolver will be invoked for refs with the file protocol
file: {
async resolve(ref: uri.URI) {
return fs.read(String(ref));
}
}
}
});
const resolved = await resolver.resolve({
definitions: {
someOASFile: {
$ref: "./main.oas2.yml#/definitions/user"
},
someMarkdownFile: {
$ref: "https://foo.com/intro.md"
}
}
});
// ==> result is the original object, with refs resolved and replaced
expect(resolved.result).toEqual({
definitions: {
someOASFile: {
// ... the data located in the relative file ./main.oas2.yml and inner json path #/definitions/user
},
someMarkdownFile: {
// ... the data located at the url
}
}
});
If there are relative remote references (for example, a relative file path ../model.json), then the location of the sourcebaseUri
data must be specified via the option. Relative references will be dereferenced against this baseUri.
`ts
import { Resolver } from "@stoplight/json-ref-resolver";
import * as fs from "fs";
import * as URI from "urijs";
const resolver = new Resolver({
readers: {
file: {
async read(ref: uri.URI) {
return fs.read(String(ref));
}
}
}
});
const sourcePath = "/specs/api.json";
const sourceData = fs.readSync(sourcePath);
// sourceData === {
// user: {
// $ref: "../models/user.json"
// }
// }
const resolved = await resolver.resolve(sourceData, {
// Indicate where the sourceData being resolved lives, so that relative remote references can be fetched and resolved.
baseUri: new URI(sourcePath)
});
expect(resolved.result).toEqual({
user: {
// ... the user object defined in ../models/user.json
}
});
In the above example, the user $ref will resolve to /models/user.json, because ../models/user.json is resolved against the baseUri of the current document (which was indicated at /specs/api.json`). Relative references will not work if the source document has no baseUri set.
This is a simplistic example of a reader. You can create your own, but we have built some [readers][json-ref-readers] which you might find useful.
If you are interested in contributing to Spectral itself, check out our contributing docs to get started.
[json-ref-readers]: https://github.com/stoplightio/json-ref-readers/