inherits 2.0.4: inherits

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/inherits@2.0.4
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/inherits@2.0.4
Demonstrate these symbols/APIs:
  - inherits
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@11.8.0
  - runtime: node@24.13.1

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:eed6578a56bfb340796d82be4dcb7f058ce5a9e9b04b34e23e798e9f6cc012d9","constraints":{"executionContext":"node"},"contract":["inherits establishes prototype inheritance between constructor functions so instances inherit methods from super constructor","inherits sets the super_ property on the child constructor to reference the super constructor","inherits maintains correct constructor reference on child prototype pointing back to child constructor","instances of child constructor satisfy instanceof checks for both child and super constructor","calling super constructor within child constructor properly initializes inherited own properties","overriding methods on child prototype does not affect super constructor prototype methods","multi-level prototype inheritance chains function correctly across generations"],"goal":"verify pkg:npm/inherits@2.0.4","kind":"HOW","packages":["pkg:npm/inherits@2.0.4"],"schemaVersion":1,"symbols":["inherits"]},"contractCommand":["node","test/contract.js"],"environment":{"arch":"x64","ecosystem":"npm","executionContext":"node","language":"javascript","moduleSystem":"cjs","os":"linux","packageManager":"npm","packageManagerVersion":"10","runtime":"node","runtimeVersion":"22","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/inherits@2.0.4"],"schemaVersion":1,"symbols":["inherits"],"verifierAdapter":"node-typescript@1"}

'use strict';

var inherits = require('inherits');

function setupInheritance(ctor, superCtor) {
  inherits(ctor, superCtor);
}

module.exports = {
  inherits: inherits,
  setupInheritance: setupInheritance
};

{
  "name": "sample-inherits",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-inherits",
      "version": "1.0.0",
      "dependencies": {
        "inherits": "2.0.4"
      }
    },
    "node_modules/inherits": {
      "version": "2.0.4",
      "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.4.tgz",
      "integrity": "sha512-k/vGaX4/Yla3WzyMCvTQOXYeIHvqOKtnqBduzTHpzpQZzAskKMhZ2K+EnBiSM9zGSoIFeMpXKxa4dYeZIQqewQ==",
      "license": "ISC"
    }
  }
}

{
  "name": "sample-inherits",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification of inherits package",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "inherits": "2.0.4"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/inherits@2.0.4",
  "kind": "HOW",
  "packages": [
    "pkg:npm/inherits@2.0.4"
  ],
  "symbols": [
    "inherits"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@11.8.0",
    "runtime": "node@24.13.1"
  }
}

'use strict';

var assert = require('assert');
var sample = require('../index.js');
var inherits = sample.inherits;

// 1. Basic prototype inheritance and method inheritance
function SuperClass(name) {
  this.name = name || 'super';
}
SuperClass.prototype.greet = function () {
  return 'Hello, ' + this.name;
};
SuperClass.prototype.sharedValue = 100;

function SubClass(name, extra) {
  SuperClass.call(this, name);
  this.extra = extra;
}
inherits(SubClass, SuperClass);

var sub = new SubClass('tester', 42);

// Contract: inherits establishes prototype inheritance between constructor functions so instances inherit methods from super constructor
assert.strictEqual(sub.greet(), 'Hello, tester');
assert.strictEqual(sub.sharedValue, 100);

// Contract: inherits sets the super_ property on the child constructor to reference the super constructor
assert.strictEqual(SubClass.super_, SuperClass);

// Contract: inherits maintains correct constructor reference on child prototype pointing back to child constructor
assert.strictEqual(SubClass.prototype.constructor, SubClass);
assert.strictEqual(sub.constructor, SubClass);

// Contract: instances of child constructor satisfy instanceof checks for both child and super constructor
assert.strictEqual(sub instanceof SubClass, true);
assert.strictEqual(sub instanceof SuperClass, true);
assert.strictEqual(sub instanceof Object, true);

// Contract: calling super constructor within child constructor properly initializes inherited own properties
assert.strictEqual(sub.name, 'tester');
assert.strictEqual(sub.extra, 42);

// Contract: overriding methods on child prototype does not affect super constructor prototype methods
SubClass.prototype.greet = function () {
  return 'Sub: ' + this.name;
};
var superObj = new SuperClass('original');
assert.strictEqual(sub.greet(), 'Sub: tester');
assert.strictEqual(superObj.greet(), 'Hello, original');

// Contract: multi-level prototype inheritance chains function correctly across generations
function GrandChild(name, extra, level) {
  SubClass.call(this, name, extra);
  this.level = level;
}
sample.setupInheritance(GrandChild, SubClass);

GrandChild.prototype.getLevel = function () {
  return this.level;
};

var grand = new GrandChild('leaf', 99, 3);
assert.strictEqual(grand.name, 'leaf');
assert.strictEqual(grand.extra, 99);
assert.strictEqual(grand.level, 3);
assert.strictEqual(grand.getLevel(), 3);
assert.strictEqual(grand.greet(), 'Sub: leaf');
assert.strictEqual(grand.sharedValue, 100);
assert.strictEqual(GrandChild.super_, SubClass);
assert.strictEqual(grand instanceof GrandChild, true);
assert.strictEqual(grand instanceof SubClass, true);
assert.strictEqual(grand instanceof SuperClass, true);
assert.strictEqual(grand.constructor, GrandChild);

console.log('PASS: inherits contract verified');