CodeSampleX

Sample

check-error 2.1.3

Verified sample for npm check-error 2.1.3. The contract ran on node 22 · linux alpine/x64 · docker and passed: compatibleInstance returns true when thrown…

sha256:05384df089e1046ce08c3fcaaced2b5a257cfcfdf89b38c16421aaa23fe09e19

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 node 22.23 linux 24 · ubuntu · glibc 2.39 x64 node 22.23 javascript 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@1node:22-alpine@sha256:c610fcdfb1d5…
2026-08-26

Case

HOW
Goal
verify pkg:npm/check-error@2.1.3
Packages
Environment
node 22.23.2
Created
2026-08-26T09:08:10Z

Contract

  1. compatibleInstance returns true when thrown error strictly equals errorLike instance and false otherwise
  2. compatibleConstructor matches errors by constructor function or instance inheritance
  3. compatibleMessage verifies error messages using string substring or regular expression matching
  4. getMessage extracts message string from Error instances or string values
  5. getConstructorName retrieves the constructor name from error instances and constructor functions

Files

  • PROMPT.md
  • csx.json
  • package-lock.json
  • package.json
  • spec.json
  • 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/check-error@2.1.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/check-error@2.1.3

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
{"case":{"caseId":"case:sha256:186357eff31284db85020ef94caf762d4414d505f9fcd98be50e5a06ccdc8e71","contract":["compatibleInstance returns true when thrown error strictly equals errorLike instance and false otherwise","compatibleConstructor matches errors by constructor function or instance inheritance","compatibleMessage verifies error messages using string substring or regular expression matching","getMessage extracts message string from Error instances or string values","getConstructorName retrieves the constructor name from error instances and constructor functions"],"goal":"verify pkg:npm/check-error@2.1.3","kind":"HOW","packages":["pkg:npm/check-error@2.1.3"],"schemaVersion":1},"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","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","verifierAdapter":"node-typescript@1"}
package-lock.json
{
  "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"
      }
    }
  }
}
package.json
{
  "name": "sample-check-error",
  "version": "1.0.0",
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "check-error": "2.1.3"
  }
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/check-error@2.1.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/check-error@2.1.3"
  ]
}
test/contract.mjs
import assert from 'node:assert/strict';
import {
  compatibleInstance,
  compatibleConstructor,
  compatibleMessage,
  getMessage,
  getConstructorName
} from 'check-error';

// 1. compatibleInstance returns true when thrown error strictly equals errorLike instance and false otherwise
const err1 = new Error('test error');
const err2 = new Error('test error');
assert.equal(compatibleInstance(err1, err1), true);
assert.equal(compatibleInstance(err1, err2), false);
assert.equal(compatibleInstance(err1, null), false);
assert.equal(compatibleInstance(err1, 'test error'), false);
assert.equal(compatibleInstance(err1, Error), false);

// 2. compatibleConstructor matches errors by constructor function or instance inheritance
class CustomError extends Error {}
const customErr = new CustomError('custom failure');
const typeErr = new TypeError('type failure');

assert.equal(compatibleConstructor(err1, Error), true);
assert.equal(compatibleConstructor(typeErr, TypeError), true);
assert.equal(compatibleConstructor(typeErr, Error), true);
assert.equal(compatibleConstructor(customErr, CustomError), true);
assert.equal(compatibleConstructor(customErr, Error), true);
assert.equal(compatibleConstructor(customErr, err1), true);
assert.equal(compatibleConstructor(err1, customErr), false);
assert.equal(compatibleConstructor(err1, TypeError), false);
assert.equal(compatibleConstructor(err1, {}), false);

// 3. compatibleMessage verifies error messages using string substring or regular expression matching
const msgErr = new Error('Failed to connect to host: 127.0.0.1');
assert.equal(compatibleMessage(msgErr, 'Failed to connect'), true);
assert.equal(compatibleMessage(msgErr, '127.0.0.1'), true);
assert.equal(compatibleMessage(msgErr, 'database error'), false);
assert.equal(compatibleMessage(msgErr, /^Failed to connect/), true);
assert.equal(compatibleMessage(msgErr, /host: \d+\.\d+\.\d+\.\d+/), true);
assert.equal(compatibleMessage(msgErr, /^database/), false);
assert.equal(compatibleMessage('raw string error', 'string error'), true);
assert.equal(compatibleMessage('raw string error', /^raw/), true);

// 4. getMessage extracts message string from Error instances or string values
assert.equal(getMessage(new Error('something went wrong')), 'something went wrong');
assert.equal(getMessage('direct error message'), 'direct error message');
assert.equal(getMessage(new Error()), '');
assert.equal(getMessage(null), '');
assert.equal(getMessage(undefined), '');

// 5. getConstructorName retrieves the constructor name from error instances and constructor functions
assert.equal(getConstructorName(new TypeError('type')), 'TypeError');
assert.equal(getConstructorName(new RangeError('range')), 'RangeError');
assert.equal(getConstructorName(TypeError), 'TypeError');
assert.equal(getConstructorName(customErr), 'CustomError');
assert.equal(getConstructorName(CustomError), 'CustomError');

Origin Seeder

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