CodeSampleX

Sample

@babel/plugin-transform-class-properties 7.29.7

Verified sample for npm @babel/plugin-transform-class-properties 7.29.7. The contract ran on node 22 · linux alpine/x64 · docker and passed.

sha256:1423a35b1039a868ee0680b9c8ed7e55056cf3b4efca1929d36a97ed7a08d531

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment linux 24 · ubuntu · glibc 2.39 x64 npm

Verification-run environments

Environment Contract Stages Run
node 22 · linux alpine/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1		 2026-08-21

Case

HOW
Goal
verify pkg:npm/%40babel/plugin-transform-class-properties@7.29.7
Packages
Created
2026-08-21T06:38:15Z

Contract

  1. Plugin default export is a function factory asserting Babel version compatibility
  2. Plugin factory returns an object named transform-class-properties with manipulateOptions, pre, and visitor
  3. manipulateOptions adds classProperties and classPrivateProperties to parser plugins array
  4. Plugin accepts options including loose mode configuration
  5. Visitor provides Class and ExportDefaultDeclaration visitor methods for AST transformation
  6. Module helpers instantiate the plugin, configure parser options, and extract visitors

Files

  • PROMPT.md
  • csx.json
  • package-lock.json
  • package.json
  • spec.json
  • src/index.mjs
  • test/contract.mjs

Download the source artifact (tar.gz)

Source

PROMPT.md
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/%40babel/plugin-transform-class-properties@7.29.7
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40babel/plugin-transform-class-properties@7.29.7

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.
csx.json
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package-lock.json
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package.json
{
  "name": "sample-babel-plugin-transform-class-properties",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "@babel/plugin-transform-class-properties": "7.29.7"
  }
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/%40babel/plugin-transform-class-properties@7.29.7",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40babel/plugin-transform-class-properties@7.29.7"
  ]
}
src/index.mjs
import classPropertiesPlugin from '@babel/plugin-transform-class-properties';

/**
 * Creates and initializes the transform-class-properties plugin instance.
 * @param {object} [api] - Babel API mock or instance with assertVersion.
 * @param {object} [options] - Plugin options such as { loose: boolean }.
 * @returns {object} Plugin instance object with name, manipulateOptions, pre, and visitor.
 */
export function createClassPropertiesPlugin(api, options = {}) {
  const plugin = classPropertiesPlugin.default || classPropertiesPlugin;
  const babelApi = api || {
    assertVersion: (range) => Boolean(range)
  };
  return plugin(babelApi, options);
}

/**
 * Applies class properties options manipulation to Babel parser options.
 * @param {object} pluginInstance - The plugin instance returned by createClassPropertiesPlugin.
 * @param {object} [parserOpts] - Parser options object containing plugins array.
 * @returns {{ parserPlugins: Array }}
 */
export function applyClassPropertiesParserOptions(pluginInstance, parserOpts = { plugins: [] }) {
  if (typeof pluginInstance.manipulateOptions === 'function') {
    pluginInstance.manipulateOptions({}, parserOpts);
  }
  return {
    parserPlugins: parserOpts.plugins
  };
}

/**
 * Retrieves the AST visitor from the plugin instance.
 * @param {object} pluginInstance - The plugin instance returned by createClassPropertiesPlugin.
 * @returns {object} The visitor object containing AST node visitor methods.
 */
export function getClassPropertiesVisitor(pluginInstance) {
  return pluginInstance.visitor || {};
}
test/contract.mjs
import assert from 'node:assert/strict';
import classPropertiesPlugin from '@babel/plugin-transform-class-properties';
import {
  createClassPropertiesPlugin,
  applyClassPropertiesParserOptions,
  getClassPropertiesVisitor
} from '../src/index.mjs';

// 1. Verify default export is the plugin factory function
const plugin = classPropertiesPlugin.default || classPropertiesPlugin;
assert.equal(typeof plugin, 'function', 'Plugin export must be a function');

// 2. Verify assertVersion check and returned plugin structure
let assertedVersionRange = null;
const mockApi = {
  assertVersion(range) {
    assertedVersionRange = range;
  }
};
const instance = plugin(mockApi, {});
assert.equal(assertedVersionRange, '^7.0.0-0 || ^8.0.0-0', 'Plugin must assert Babel version range');
assert.equal(typeof instance, 'object', 'Plugin factory must return an object');
assert.equal(instance.name, 'transform-class-properties', 'Plugin name must be transform-class-properties');
assert.equal(typeof instance.manipulateOptions, 'function', 'Plugin must provide manipulateOptions function');
assert.equal(typeof instance.pre, 'function', 'Plugin must provide pre function');
assert.equal(typeof instance.visitor, 'object', 'Plugin must provide visitor object');
assert.equal(typeof instance.visitor.Class, 'function', 'Visitor must provide Class method');
assert.equal(typeof instance.visitor.ExportDefaultDeclaration, 'function', 'Visitor must provide ExportDefaultDeclaration method');

// 3. Verify manipulateOptions adds classProperties and classPrivateProperties plugins
const parserOpts1 = { plugins: [] };
instance.manipulateOptions({}, parserOpts1);
assert.deepEqual(
  parserOpts1.plugins,
  ['classProperties', 'classPrivateProperties'],
  'manipulateOptions must add classProperties and classPrivateProperties to parser plugins'
);

// 4. Verify manipulateOptions preserves existing parser plugins
const parserOpts2 = { plugins: ['jsx'] };
instance.manipulateOptions({}, parserOpts2);
assert.deepEqual(
  parserOpts2.plugins,
  ['jsx', 'classProperties', 'classPrivateProperties'],
  'manipulateOptions must preserve existing parser plugins'
);

// 5. Verify loose option configuration
const instanceLoose = plugin(mockApi, { loose: true });
assert.equal(instanceLoose.name, 'transform-class-properties');
assert.equal(typeof instanceLoose.visitor, 'object');
assert.equal(typeof instanceLoose.visitor.Class, 'function');

const instanceNonLoose = plugin(mockApi, { loose: false });
assert.equal(instanceNonLoose.name, 'transform-class-properties');
assert.equal(typeof instanceNonLoose.visitor, 'object');
assert.equal(typeof instanceNonLoose.visitor.Class, 'function');

// 6. Verify helper functions from src/index.mjs
const helperInstance = createClassPropertiesPlugin();
assert.equal(helperInstance.name, 'transform-class-properties');

const helperParserResult = applyClassPropertiesParserOptions(helperInstance);
assert.deepEqual(helperParserResult.parserPlugins, ['classProperties', 'classPrivateProperties']);

const visitor = getClassPropertiesVisitor(helperInstance);
assert.equal(typeof visitor.Class, 'function');
assert.equal(typeof visitor.ExportDefaultDeclaration, 'function');

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

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