@nodable/entities 3.0.0: EntityDecoder, EntityEncoder

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/%40nodable/entities@3.0.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40nodable/entities@3.0.0
Demonstrate these symbols/APIs:
  - EntityDecoder
  - EntityEncoder
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:e49f448aa12069340a42f29c2eb593fa5f268afdf484d34cf81395d797536b5f","constraints":{"executionContext":"node"},"contract":["EntityEncoder throws an error when constructed without namedEntities while encodeAllNamed is true","EntityEncoder with namedEntities encodes XML-unsafe characters and named entity characters","EntityEncoder with encodeAllNamed set to false encodes only XML-unsafe characters without requiring namedEntities","EntityEncoder maxReplacements enforces cumulative replacement limits and reset restores capacity","EntityDecoder with namedEntities decodes named entities, XML entities, and numeric character references","EntityDecoder supports dynamic external and input entities with reset clearing document input entities","EntityDecoder registration hooks support ENTITY_ACTION.BLOCK and ENTITY_ACTION.THROW on entity definitions"],"goal":"verify pkg:npm/%40nodable/entities@3.0.0","kind":"HOW","packages":["pkg:npm/%40nodable/entities@3.0.0"],"schemaVersion":1,"symbols":["EntityDecoder","EntityEncoder"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40nodable/entities@3.0.0"],"schemaVersion":1,"subject":"pkg:npm/%40nodable/entities@3.0.0","symbols":["EntityDecoder","EntityEncoder"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-nodable-entities",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-nodable-entities",
      "version": "1.0.0",
      "dependencies": {
        "@nodable/entities": "3.0.0"
      }
    },
    "node_modules/@nodable/entities": {
      "version": "3.0.0",
      "resolved": "https://registry.npmjs.org/@nodable/entities/-/entities-3.0.0.tgz",
      "integrity": "sha512-8L9xFeTYKhm49xfIypoe2W5wV1m/3Z58kT+7kR9A8OyFxcPduI4VmxaUMQyKYrRjUoLLSXv6EKKID5Tvj9cUVw==",
      "funding": [
        {
          "type": "github",
          "url": "https://github.com/sponsors/nodable"
        }
      ],
      "license": "MIT"
    }
  }
}

{
  "name": "sample-nodable-entities",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "dependencies": {
    "@nodable/entities": "3.0.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/%40nodable/entities@3.0.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40nodable/entities@3.0.0"
  ],
  "symbols": [
    "EntityDecoder",
    "EntityEncoder"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

import assert from 'node:assert/strict';
import {
  EntityEncoder,
  EntityDecoder,
  ALL_ENTITIES,
  ENTITY_ACTION,
} from '@nodable/entities';

// 1. EntityEncoder throws an error when constructed without namedEntities while encodeAllNamed is true
assert.throws(
  () => new EntityEncoder(),
  /encodeAllNamed is true but no `namedEntities` was provided/
);

// 2. EntityEncoder with namedEntities encodes XML-unsafe characters and named entity characters
const fullEncoder = new EntityEncoder({ namedEntities: ALL_ENTITIES });
assert.equal(
  fullEncoder.encode('Hello € 2026 & <world>'),
  'Hello &euro; 2026 &amp; &lt;world&gt;'
);

// 3. EntityEncoder with encodeAllNamed set to false encodes only XML-unsafe characters without requiring namedEntities
const xmlOnlyEncoder = new EntityEncoder({ encodeAllNamed: false });
assert.equal(
  xmlOnlyEncoder.encode('Hello € 2026 & <world>'),
  'Hello € 2026 &amp; &lt;world&gt;'
);

// 4. EntityEncoder maxReplacements enforces cumulative replacement limits and reset restores capacity
const limitedEncoder = new EntityEncoder({ encodeAllNamed: false, maxReplacements: 2 });
assert.equal(limitedEncoder.encode('<a>&<b>'), '&lt;a&gt;&<b>');
assert.equal(limitedEncoder.encode('<c>'), '<c>');
limitedEncoder.reset();
assert.equal(limitedEncoder.encode('<a>&<b>'), '&lt;a&gt;&<b>');

// 5. EntityDecoder with namedEntities decodes named entities, XML entities, and numeric character references
const decoder = new EntityDecoder({ namedEntities: ALL_ENTITIES });
assert.equal(
  decoder.decode('Hello &euro; 2026 &amp; &lt;world&gt; &#169; &#x26;'),
  'Hello € 2026 & <world> © &'
);

// 6. EntityDecoder supports dynamic external and input entities with reset clearing document input entities
const customDecoder = new EntityDecoder();
customDecoder.setExternalEntities({ org: 'Acme Corp' });
customDecoder.addInputEntities({ item: 'Widget' });
assert.equal(
  customDecoder.decode('&org; makes &item; &lt;safe&gt;'),
  'Acme Corp makes Widget <safe>'
);
customDecoder.reset();
assert.equal(
  customDecoder.decode('&org; makes &item; &lt;safe&gt;'),
  'Acme Corp makes &item; <safe>'
);

// 7. EntityDecoder registration hooks support ENTITY_ACTION.BLOCK and ENTITY_ACTION.THROW on entity definitions
const hookDecoder = new EntityDecoder({
  onExternalEntity: (name) => {
    if (name === 'dangerous') return ENTITY_ACTION.THROW;
    if (name === 'blocked') return ENTITY_ACTION.BLOCK;
    return ENTITY_ACTION.ALLOW;
  },
});
hookDecoder.setExternalEntities({ allowed: 'YES', blocked: 'NO' });
assert.equal(hookDecoder.decode('&allowed; &blocked;'), 'YES &blocked;');
assert.throws(() => {
  hookDecoder.setExternalEntities({ dangerous: 'EVIL' });
}, /Error/);

console.log('Contract tests passed successfully.');