html-escaper 2.0.2: escape and unescape HTML special characters

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: escape and unescape HTML special characters
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/html-escaper@2.0.2
Demonstrate these symbols/APIs:
  - escape
  - unescape

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:sha256:6eb5d8a249d17445a2527842f6c7092c5caed600a5afd85ffdc243994d0e819b","contract":["escape converts HTML special characters (\u0026, \u003c, \u003e, ', \") into corresponding HTML entities","escape preserves strings that do not contain HTML special characters","unescape converts HTML entities (\u0026amp;, \u0026lt;, \u0026gt;, \u0026#39;, \u0026quot;) back to original characters","unescape preserves strings without HTML entities","escape and unescape are inverse operations for valid HTML strings","escape and unescape handle empty strings and non-string inputs coerced to string"],"goal":"escape and unescape HTML special characters","kind":"HOW","packages":["pkg:npm/html-escaper@2.0.2"],"schemaVersion":1,"symbols":["escape","unescape"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/html-escaper@2.0.2"],"schemaVersion":1,"subject":"pkg:npm/html-escaper@2.0.2","symbols":["escape","unescape"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-html-escaper",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-html-escaper",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "html-escaper": "2.0.2"
      }
    },
    "node_modules/html-escaper": {
      "version": "2.0.2",
      "resolved": "https://registry.npmjs.org/html-escaper/-/html-escaper-2.0.2.tgz",
      "integrity": "sha512-H2iMtd0I4Mt5eYiapRdIDjp+XzelXQ0tFE4JS7YFwFevXXMmOp9myNrUvCg0D6ws8iqkRPBfKHgbwig1SmlLfg==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-html-escaper",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "html-escaper": "2.0.2"
  }
}

{
  "schemaVersion": 1,
  "goal": "escape and unescape HTML special characters",
  "kind": "HOW",
  "packages": [
    "pkg:npm/html-escaper@2.0.2"
  ],
  "symbols": [
    "escape",
    "unescape"
  ]
}

import htmlEscaper from 'html-escaper';

const { escape, unescape } = htmlEscaper;

/**
 * Escapes special HTML characters (&, <, >, ', ") in a string.
 * @param {string} text
 * @returns {string}
 */
export function escapeHtml(text) {
  return escape(text);
}

/**
 * Unescapes HTML entities (&amp;, &lt;, &gt;, &#39;, &quot;) back to characters.
 * @param {string} text
 * @returns {string}
 */
export function unescapeHtml(text) {
  return unescape(text);
}

export { escape, unescape };
export default htmlEscaper;

import assert from 'node:assert/strict';
import { escape, unescape, escapeHtml, unescapeHtml } from '../src/index.mjs';

// 1. escape converts HTML special characters (&, <, >, ', ") into corresponding HTML entities
{
  assert.equal(escape('&'), '&amp;');
  assert.equal(escape('<'), '&lt;');
  assert.equal(escape('>'), '&gt;');
  assert.equal(escape("'"), '&#39;');
  assert.equal(escape('"'), '&quot;');
  assert.equal(escape('&<>\x27"'), '&amp;&lt;&gt;&#39;&quot;');
  assert.equal(escapeHtml('<div id="test">\'hello\' & "world"</div>'), '&lt;div id=&quot;test&quot;&gt;&#39;hello&#39; &amp; &quot;world&quot;&lt;/div&gt;');
}

// 2. escape preserves strings that do not contain HTML special characters
{
  assert.equal(escape('hello world 123!@#$^*()_-+={}[]|:;,.?/'), 'hello world 123!@#$^*()_-+={}[]|:;,.?/');
  assert.equal(escapeHtml('plain text'), 'plain text');
}

// 3. unescape converts HTML entities (&amp;, &lt;, &gt;, &#39;, &quot;) back to original characters
{
  assert.equal(unescape('&amp;'), '&');
  assert.equal(unescape('&lt;'), '<');
  assert.equal(unescape('&gt;'), '>');
  assert.equal(unescape('&#39;'), "'");
  assert.equal(unescape('&quot;'), '"');
  assert.equal(unescape('&amp;&lt;&gt;&#39;&quot;'), '&<>\x27"');
  assert.equal(unescapeHtml('&lt;span class=&quot;tag&quot;&gt;&#39;data&#39; &amp; more&lt;/span&gt;'), '<span class="tag">\'data\' & more</span>');
}

// 4. unescape preserves strings without HTML entities
{
  assert.equal(unescape('normal text without entities'), 'normal text without entities');
  assert.equal(unescapeHtml('foo bar baz'), 'foo bar baz');
}

// 5. escape and unescape are inverse operations for valid HTML strings
{
  const testStrings = [
    '<a href="https://example.com?a=1&b=2">Link & Description</a>',
    '<span>"Double quotes" & \'Single quotes\'</span>',
    'Math: 5 > 3 & 2 < 4'
  ];

  for (const str of testStrings) {
    assert.equal(unescape(escape(str)), str);
    assert.equal(unescapeHtml(escapeHtml(str)), str);
  }
}

// 6. escape and unescape handle empty strings and non-string inputs coerced to string
{
  assert.equal(escape(''), '');
  assert.equal(unescape(''), '');
  assert.equal(escape(12345), '12345');
  assert.equal(unescape(12345), '12345');
}

console.log('Contract assertions passed.');