$ref and $id implementation

[Eomm]

From the docs, it is not clear which version of the json schema standard this library is supported.

From a quick test, I think we have few use cases that are not covered:

Therefore, "$id" MUST NOT contain a non-empty fragment, and SHOULD NOT contain an empty fragment. The absolute-URI form MUST be considered the canonical URI, regardless of the presence or absence of an empty fragment. An empty fragment is currently allowed because older meta-schemas have an empty fragment in their $id (or previously, id). A future draft may outright forbid even empty fragments in "$id".

From spec: https://json-schema.org/draft/2020-12/json-schema-core#name-the-id-keyword

This example should behave in a different way:

const assert = require('node:assert')
const { RefResolver } = require('json-schema-ref-resolver')


const inputSchema = {
  "$id": "http://example.com/root.json",
  "definitions": {
    "A": { "$id": "#foo" },
    "B": {
      "$id": "other.json",
      "definitions": {
        "X": { "$id": "#bar", type: 'string' },
        "Y": { "$id": "t/inner.json" }
      }
    },
    "C": {
      "$id": "urn:uuid:ee564b8a-7a87-4125-8c96-e9f123d6766f",
      type: 'object',
    }
  }
}

const addresSchema = {
  $id: 'relativeAddress', // Note: prefer always absolute URI like: http://mysite.com
  type: 'object',
  properties: {
    zip: { $ref: 'urn:uuid:ee564b8a-7a87-4125-8c96-e9f123d6766f' },
    city: { $ref: 'http://example.com/root.json#foo' }, // ❗️ should work
// city2: { $ref: '#foo' } // wrong syntax, ❗️ should say ref not found. triggers TypeError: Cannot read properties of null (reading '$ref')  }
}


const refResolver = new RefResolver()
refResolver.addSchema(inputSchema)
refResolver.addSchema(addresSchema)

refResolver.derefSchema('relativeAddress')
const derefSourceSchema = refResolver.getDerefSchema('relativeAddress')
console.log(derefSourceSchema)

I wrote almost the same lib: https://github.com/Eomm/json-schema-resolver
It is used in fastify-swagger, and we can get the tests to have a wider suite.
The code there can be optimized if we want to use it.

[ivan-tymoshenko]

From the docs, it is not clear which version of the json schema standard this library is supported.

This package supports a json schema draft 7 format, but I think it's not a problem to make it work with all drafts.

This example should behave in a different way

Thanks, here is fix #3.

I wrote almost the same lib: https://github.com/Eomm/json-schema-resolver

json-schema-resolver works in a bit different way. Correct me if I'm wrong, but it takes all external schemas puts them into the definition section, and updates all shema refs accordingly. This package resolves all $refs, which means you don't have any $ref keyword in your schema after dereferencing.