check-error 2.1.3: getConstructorName

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 check-error.getConstructorName in pkg:npm/check-error@2.1.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/check-error@2.1.3
Demonstrate these symbols/APIs:
  - check-error.getConstructorName

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:sha256:54260ce58b3a185c21c17856b8e5be1df7c005c5bd6df09736d8df4fa756a33d","contract":["getConstructorName returns the constructor name for standard built-in error instances","getConstructorName returns the constructor name for custom error class instances","getConstructorName returns the function name when passed an error constructor directly","getConstructorName returns the instance name property when constructor is an anonymous function","getConstructorName returns non-error and non-function values as-is"],"goal":"verify check-error.getConstructorName in pkg:npm/check-error@2.1.3","kind":"HOW","packages":["pkg:npm/check-error@2.1.3"],"schemaVersion":1,"symbols":["check-error.getConstructorName"]},"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/check-error@2.1.3"],"schemaVersion":1,"subject":"pkg:npm/check-error@2.1.3","symbols":["check-error.getConstructorName"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-check-error",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-check-error",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "check-error": "2.1.3"
      }
    },
    "node_modules/check-error": {
      "version": "2.1.3",
      "resolved": "https://registry.npmjs.org/check-error/-/check-error-2.1.3.tgz",
      "integrity": "sha512-PAJdDJusoxnwm1VwW07VWwUN1sl7smmC3OKggvndJFadxxDRyFJBX/ggnu/KE4kQAB7a3Dp8f/YXC1FlUprWmA==",
      "license": "MIT",
      "engines": {
        "node": ">= 16"
      }
    }
  }
}

{
  "name": "sample-check-error",
  "version": "1.0.0",
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "check-error": "2.1.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify check-error.getConstructorName in pkg:npm/check-error@2.1.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/check-error@2.1.3"
  ],
  "symbols": [
    "check-error.getConstructorName"
  ]
}

import assert from 'node:assert/strict';
import { getConstructorName } from 'check-error';

// 1. getConstructorName returns the constructor name for standard built-in error instances
assert.equal(getConstructorName(new Error('standard')), 'Error');
assert.equal(getConstructorName(new TypeError('type')), 'TypeError');
assert.equal(getConstructorName(new RangeError('range')), 'RangeError');
assert.equal(getConstructorName(new SyntaxError('syntax')), 'SyntaxError');
assert.equal(getConstructorName(new URIError('uri')), 'URIError');

// 2. getConstructorName returns the constructor name for custom error class instances
class CustomAppError extends Error {}
class SpecificServiceError extends CustomAppError {}

assert.equal(getConstructorName(new CustomAppError('custom')), 'CustomAppError');
assert.equal(getConstructorName(new SpecificServiceError('specific')), 'SpecificServiceError');

// 3. getConstructorName returns the function name when passed an error constructor directly
assert.equal(getConstructorName(Error), 'Error');
assert.equal(getConstructorName(TypeError), 'TypeError');
assert.equal(getConstructorName(RangeError), 'RangeError');
assert.equal(getConstructorName(CustomAppError), 'CustomAppError');
assert.equal(getConstructorName(SpecificServiceError), 'SpecificServiceError');

// 4. getConstructorName returns the instance name property when constructor is an anonymous function
const AnonError = (function () {
  return function () {
    this.name = 'DerivedAnonError';
  };
})();
assert.equal(getConstructorName(AnonError), 'DerivedAnonError');

const NamelessAnon = (function () {
  return function () {};
})();
assert.equal(getConstructorName(NamelessAnon), '');

// 5. getConstructorName returns non-error and non-function values as-is
assert.equal(getConstructorName('custom-name-string'), 'custom-name-string');
assert.equal(getConstructorName(123), 123);
assert.equal(getConstructorName(null), null);
assert.equal(getConstructorName(undefined), undefined);
const obj = { foo: 'bar' };
assert.equal(getConstructorName(obj), obj);

console.log('All check-error.getConstructorName contract assertions passed.');