Install

npm install @maxjay/patchwork-ajv

Requires @maxjay/patchwork as a peer dependency if you're passing Engine or NodeEngine instances.

Usage

Validate an Engine's draft

import { Engine } from '@maxjay/patchwork';
import { validate } from '@maxjay/patchwork-ajv';

const schema = {
  type: 'object',
  properties: {
    host: { type: 'string' },
    port: { type: 'number' },
  },
  required: ['host', 'port'],
};

const engine = new Engine({ host: 'localhost', port: 8080 });
engine.replace('$.port', 'oops'); // type mismatch

const errors = validate(engine, schema);
// [{ instancePath: '/port', keyword: 'type', message: 'must be number', ... }]

validate reads engine.draft and runs it through AJV. It returns an empty array when the draft is valid.

Validate a NodeEngine (scoped lens)

const nodeEngine = engine.getNodeEngine('$.server');
const errors = validate(nodeEngine, serverSchema);

nodeEngine.draft is the subtree — validation is scoped to it.

Validate a plain value

You don't need an Engine at all. Pass any value directly:

const errors = validate({ host: 'localhost', port: 8080 }, schema);

validate detects the presence of a .draft property to decide whether to unwrap.

Patchwork schema extensions

Patchwork schemas can include x-key and x-ordered on array nodes for identity-based diffing:

const schema = {
  type: 'object',
  properties: {
    users: {
      type: 'array',
      'x-key': 'id',        // patchwork extension — identity field for diffing
      'x-ordered': true,    // patchwork extension — position changes emit as move ops
      items: {
        type: 'object',
        properties: {
          id: { type: 'string' },
          name: { type: 'string' },
        },
        required: ['id'],
      },
    },
  },
};

// Works fine — x-key and x-ordered are registered as no-ops in AJV
const errors = validate(engine, schema);

You can pass the same schema object to both new Engine(base, { schema }) and validate() — no stripping or copying needed.

API

validate(target, schema): ErrorObject[]

| Parameter | Type | Description | |---|---|---| | target | Engine \| NodeEngine \| { draft: unknown } \| unknown | If the value has a .draft property, that property is validated. Otherwise the value itself is validated. | | schema | object | Any valid JSON Schema object. Patchwork's x-key and x-ordered extensions are ignored by AJV. |

Returns AJV's ErrorObject[]. Empty array means valid.

ErrorObject

Re-exported from AJV for convenience:

import { type ErrorObject } from '@maxjay/patchwork-ajv';

Key fields:

| Field | Description | |---|---| | instancePath | JSON Pointer to the failing value (e.g. /users/0/id) | | keyword | The failing keyword (required, type, minimum, …) | | message | Human-readable error string | | params | Keyword-specific details (e.g. { missingProperty: 'id' }) |