CodeSampleX

Sample

@babel/plugin-transform-duplicate-keys 7.29.7

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

sha256:74c04303144b550e67c36e463135739c62ac907244a89e29db038efa7e8d9996

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-duplicate-keys@7.29.7
Packages
Created
2026-08-21T06:54:50Z

Contract

  1. Plugin default export is a function factory asserting Babel 7 compatibility
  2. Plugin factory returns an object named transform-duplicate-keys with ObjectExpression visitor method
  3. ObjectExpression visitor marks duplicate data properties as computed string literals
  4. ObjectExpression visitor detects duplicates across getters, setters, and data properties
  5. ObjectExpression visitor ignores spread elements and already computed properties
  6. Module helpers instantiate plugin and transform duplicate keys in AST object expressions

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-duplicate-keys@7.29.7
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40babel/plugin-transform-duplicate-keys@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": "verify-babel-plugin-transform-duplicate-keys",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "@babel/plugin-transform-duplicate-keys": "7.29.7"
  }
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/%40babel/plugin-transform-duplicate-keys@7.29.7",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40babel/plugin-transform-duplicate-keys@7.29.7"
  ]
}
src/index.mjs
import duplicateKeysPlugin from '@babel/plugin-transform-duplicate-keys';

/**
 * Creates and initializes the duplicate-keys plugin instance.
 * @param {object} [api] - Optional Babel API object.
 * @param {object} [options] - Optional plugin options.
 * @returns {object} Plugin instance object with name and visitor.
 */
export function createDuplicateKeysPlugin(api, options = {}) {
  const plugin = duplicateKeysPlugin.default || duplicateKeysPlugin;
  const babelApi = api || {
    assertVersion: (range) => Boolean(range)
  };
  return plugin(babelApi, options);
}

/**
 * Transforms an ObjectExpression AST path using the duplicate-keys visitor.
 * @param {object} pluginInstance - Plugin instance returned by createDuplicateKeysPlugin.
 * @param {object} path - Mock or real Babel AST path for ObjectExpression.
 */
export function applyDuplicateKeysTransform(pluginInstance, path) {
  if (pluginInstance.visitor && typeof pluginInstance.visitor.ObjectExpression === 'function') {
    pluginInstance.visitor.ObjectExpression(path);
  }
}
test/contract.mjs
import assert from 'node:assert/strict';
import duplicateKeysPlugin from '@babel/plugin-transform-duplicate-keys';
import { createDuplicateKeysPlugin, applyDuplicateKeysTransform } from '../src/index.mjs';

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

// 2. Verify assertVersion check and plugin structure
let assertedVersion = null;
const mockApi = {
  assertVersion(version) {
    assertedVersion = version;
  }
};
const instance = plugin(mockApi, {});
assert.equal(assertedVersion, 7, 'Plugin must assert Babel version 7 compatibility');
assert.equal(typeof instance, 'object', 'Plugin factory must return an object');
assert.equal(instance.name, 'transform-duplicate-keys', 'Plugin name must be transform-duplicate-keys');
assert.equal(typeof instance.visitor, 'object', 'Plugin must provide a visitor object');
assert.equal(typeof instance.visitor.ObjectExpression, 'function', 'Visitor must provide ObjectExpression method');

// Helper to construct a mock ObjectProperty
function createMockProperty(nameOrValue, isIdentifier = true, kind = 'init', computed = false) {
  return {
    type: 'ObjectProperty',
    key: isIdentifier
      ? { type: 'Identifier', name: nameOrValue }
      : { type: 'StringLiteral', value: String(nameOrValue) },
    value: { type: 'NumericLiteral', value: 1 },
    computed,
    kind
  };
}

// 3. Verify ObjectExpression visitor marks duplicate data properties as computed string literals
{
  const prop1 = createMockProperty('a', true, 'init');
  const prop2 = createMockProperty('a', true, 'init');
  const prop3 = createMockProperty('b', true, 'init');

  const path = {
    node: {
      type: 'ObjectExpression',
      properties: [prop1, prop2, prop3]
    }
  };

  instance.visitor.ObjectExpression(path);

  assert.equal(prop1.computed, false, 'First property must not be marked computed');
  assert.equal(prop2.computed, true, 'Duplicate property must be marked computed');
  assert.equal(prop2.key.type, 'StringLiteral', 'Duplicate property key must be transformed to StringLiteral');
  assert.equal(prop2.key.value, 'a', 'Duplicate property key value must match original name');
  assert.equal(prop3.computed, false, 'Unique property must not be marked computed');
}

// 4. Verify string literal duplicate keys
{
  const prop1 = createMockProperty('foo', false, 'init');
  const prop2 = createMockProperty('foo', false, 'init');

  const path = {
    node: {
      type: 'ObjectExpression',
      properties: [prop1, prop2]
    }
  };

  instance.visitor.ObjectExpression(path);

  assert.equal(prop1.computed, false, 'First string literal property must remain uncomputed');
  assert.equal(prop2.computed, true, 'Second string literal property must be marked computed');
  assert.equal(prop2.key.type, 'StringLiteral');
  assert.equal(prop2.key.value, 'foo');
}

// 5. Verify ObjectExpression visitor detects duplicates across getters, setters, and data properties
{
  // Test duplicate getters
  const get1 = createMockProperty('size', true, 'get');
  const get2 = createMockProperty('size', true, 'get');
  const getPath = {
    node: {
      type: 'ObjectExpression',
      properties: [get1, get2]
    }
  };
  instance.visitor.ObjectExpression(getPath);
  assert.equal(get1.computed, false);
  assert.equal(get2.computed, true);
  assert.equal(get2.key.type, 'StringLiteral');
  assert.equal(get2.key.value, 'size');

  // Test getter + setter (valid pair, not duplicate)
  const getProp = createMockProperty('count', true, 'get');
  const setProp = createMockProperty('count', true, 'set');
  const getterSetterPath = {
    node: {
      type: 'ObjectExpression',
      properties: [getProp, setProp]
    }
  };
  instance.visitor.ObjectExpression(getterSetterPath);
  assert.equal(getProp.computed, false, 'Getter in get/set pair must not be duplicate');
  assert.equal(setProp.computed, false, 'Setter in get/set pair must not be duplicate');

  // Test getter followed by data property (conflict -> duplicate)
  const getProp2 = createMockProperty('total', true, 'get');
  const dataProp2 = createMockProperty('total', true, 'init');
  const conflictPath = {
    node: {
      type: 'ObjectExpression',
      properties: [getProp2, dataProp2]
    }
  };
  instance.visitor.ObjectExpression(conflictPath);
  assert.equal(getProp2.computed, false);
  assert.equal(dataProp2.computed, true);
  assert.equal(dataProp2.key.value, 'total');
}

// 6. Verify ObjectExpression visitor ignores spread elements and already computed properties
{
  const spreadNode = {
    type: 'SpreadElement',
    argument: { type: 'Identifier', name: 'rest' }
  };
  const computedProp = {
    type: 'ObjectProperty',
    key: { type: 'Identifier', name: 'dynamicKey' },
    value: { type: 'NumericLiteral', value: 42 },
    computed: true,
    kind: 'init'
  };
  const normalProp = createMockProperty('staticKey', true, 'init');

  const path = {
    node: {
      type: 'ObjectExpression',
      properties: [spreadNode, computedProp, normalProp]
    }
  };

  instance.visitor.ObjectExpression(path);
  assert.equal(normalProp.computed, false, 'Static property must remain unchanged');
  assert.equal(computedProp.computed, true, 'Computed property must remain unchanged');
}

// 7. Verify helper functions from src/index.mjs
{
  const helperInstance = createDuplicateKeysPlugin();
  assert.equal(helperInstance.name, 'transform-duplicate-keys');

  const propA1 = createMockProperty('x', true, 'init');
  const propA2 = createMockProperty('x', true, 'init');
  const helperPath = {
    node: {
      type: 'ObjectExpression',
      properties: [propA1, propA2]
    }
  };

  applyDuplicateKeysTransform(helperInstance, helperPath);
  assert.equal(propA1.computed, false);
  assert.equal(propA2.computed, true);
  assert.equal(propA2.key.value, 'x');
}

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

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