json-schema-resolver

What is json-schema-resolver?

The json-schema-resolver npm package is designed to resolve JSON schema references, allowing you to dereference $ref pointers within your JSON schemas. This is particularly useful for validating complex JSON structures that reference other schemas.

What are json-schema-resolver's main functionalities?

Resolving JSON Schema References

This feature allows you to resolve $ref pointers within a JSON schema. The code sample demonstrates how to use the json-schema-resolver package to dereference a schema that includes a reference to another schema.

const resolver = require('json-schema-resolver');
const schema = {
  "$id": "http://example.com/root.json",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "name": {
      "$ref": "http://example.com/name.json"
    }
  }
};
const resolvedSchema = resolver.resolve(schema);
console.log(JSON.stringify(resolvedSchema, null, 2));

Other packages similar to json-schema-resolver

json-schema-ref-parser

json-schema-ref-parser is a powerful library for parsing, resolving, and dereferencing JSON schema $ref pointers. It offers similar functionality to json-schema-resolver but includes additional features like bundling and dereferencing schemas with circular references.

json-schema-deref-sync

json-schema-deref-sync is a synchronous library for dereferencing JSON schema $ref pointers. It is similar to json-schema-resolver but operates synchronously, making it suitable for use cases where asynchronous operations are not desired.

json-schema-deref

json-schema-deref is another library for dereferencing JSON schema $ref pointers. It provides similar functionality to json-schema-resolver but focuses on simplicity and ease of use.

README

json-schema-resolver

Resolve all $refs in your JSON schema!
This module will resolve the $ref keyword against the externalSchemas you will provide.
By resolving the $ref keyword, means that you get back a single BIG inlined JSON schema that does not rely on any external schema. If a reference is missing, it will not throw any error.

Install

npm install json-schema-resolver

This plugin support Node.js >= 10

Usage: resolve one schema against external schemas

The $ref string is going to be modified to point to a local reference URI: #/definitions/<generated key>. Moreover, the definitions keyword will be decorated with the external schemas to get only one JSON schema resolved as output.

By default the <generated key> has the def-${index} format. You can customize it by passing a buildLocalReference function as follows:

const RefResolver = require('json-schema-resolver')

const ref = RefResolver({
  clone: true, // Clone the input schema without changing it. Default: false,
  buildLocalReference (json, baseUri, fragment, i) {
    // the `json` that is being resolved
    // the `baseUri` object of the schema. Its values is the parse result from https://www.npmjs.com/package/fast-uri
    // the `fragment` is the `$ref` string when the `$ref` is a relative reference
    // the `i` is a local counter to generate a unique key
    return `def-${i}` // default value
  }
})

const inputSchema = {
  $id: 'http://example.com/SimplePerson',
  type: 'object',
  properties: {
    name: { type: 'string' },
    address: { $ref: 'relativeAddress#' },
    houses: { type: 'array', items: { $ref: 'relativeAddress#' } }
  }
}

const addresSchema = {
  $id: 'relativeAddress', // Note: prefer always absolute URI like: http://mysite.com
  type: 'object',
  properties: {
    zip: { type: 'string' },
    city: { type: 'string' }
  }
}

const singleSchema = ref.resolve(inputSchema, { externalSchemas: [addresSchema] })
// inputSchema is untouched thanks to clone:true

singleSchema will be like:

{
  "$id": "http://example.com/SimplePerson",
  "type": "object",
  "properties": {
    "name": {
      "type": "string"
    },
    "address": {
      "$ref": "#/definitions/def-0"
    },
    "houses": {
      "type": "array",
      "items": {
        "$ref": "#/definitions/def-0"
      }
    }
  },
  "definitions": {
    "def-0": {
      "$id": "relativeAddress",
      "type": "object",
      "properties": {
        "zip": {
          "type": "string"
        },
        "city": {
          "type": "string"
        }
      }
    }
  }
}

Usage: resolve multiple schemas against external shared schemas

When you have multiple schemas to resolve against a collection of shared schema you need to use this module with little changes.

This is needed to have all the same definitions path (#/definitions/<generated key>) across all the root schemas

const ref = RefResolver({
  clone: true, // Clone the input schema without changing it. Default: false
  applicationUri: 'my-application.org', // You need to provide an unique URI to resolve relative `$id`s
  externalSchemas: [addresSchema] // The schemas provided at the creation of the resolver, will be used evvery time `.resolve` will be called
})

const inputSchema = {
  $id: 'http://example.com/SimplePerson',
  type: 'object',
  properties: {
    name: { type: 'string' },
    address: { $ref: 'relativeAddress#' },
    houses: { type: 'array', items: { $ref: 'relativeAddress#' } }
  }
}

// the resolved schema DOES NOT have definitions added
const singleSchema = ref.resolve(inputSchema)
const anotherResolvedSchema = ref.resolve(input_2_Schema) // resolve schemas within the same externalSchemas

// to get the definition you need only to call:
const sharedDefinitions = ref.definitions()

Debug

To debug this module, simply set:

export DEBUG=json-schema-resolver

License

Licensed under MIT.