ajv 8.20.0: Fix ajv throwing "strict mode: unknown keyword" when compiling an existing JSON Schema

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{
  "name": "csx-sample-ajv-strict-schema",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "ajv": "8.20.0"
  }
}

import Ajv from 'ajv';

// ajv 8 turns strict mode ON by default: any keyword it does not recognize
// throws at compile time rather than being ignored as in ajv 6/7. Turning
// strict off hides real typos, so declaring the keyword is the safer fix.
// Errors also changed shape in v8 — dataPath became instancePath.
export function compileStrict(schema) {
  const ajv = new Ajv({ strict: true });
  return ajv.compile(schema);
}

export function compileWithKeyword(schema, keyword) {
  const ajv = new Ajv({ strict: true });
  ajv.addKeyword({ keyword, schemaType: 'string' });
  return ajv.compile(schema);
}

import { strict as assert } from 'node:assert';
import { compileStrict, compileWithKeyword } from '../src/index.mjs';

const schema = {
  type: 'object',
  properties: { name: { type: 'string' }, port: { type: 'integer' } },
  required: ['name'],
  'x-unit': 'milliseconds', // annotation ajv does not know
};

assert.throws(() => compileStrict(schema), /strict mode/i);

const validate = compileWithKeyword(schema, 'x-unit');
assert.equal(validate({ name: 'csx', port: 8080 }), true);

assert.equal(validate({ port: 'not-an-integer' }), false);
const codes = validate.errors.map((e) => e.keyword);
assert.ok(codes.includes('required'));
assert.equal(typeof validate.errors[0].instancePath, 'string'); // v8 name
console.log('CONTRACT PASS: ajv 8 strict mode explained and the schema compiled');