CodeSampleX

Sample

@sindresorhus/is 4.6.0

Verified sample for npm @sindresorhus/is 4.6.0. The contract ran on node 22 · linux alpine/x64 · docker and passed: is returns the correct type name string…

sha256:03b581aafcbb688b90aa8a60d0c064d39fe8f0926ad865489fa867b9f3540cf3

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
2
Signing keys that built it
1
Declared environment node 22.23 linux 24 · ubuntu · glibc 2.39 x64 node 22.23 javascript npm 10

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
node 22 · linux debian/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1node:22@sha256:8a34c4ab3ea2…
2026-09-07

Case

HOW
Goal
verify pkg:npm/%40sindresorhus/is@4.6.0
Packages
Environment
node 22.23.2
Created
2026-08-21T09:24:18Z

Contract

  1. is returns the correct type name string for primitives and objects
  2. is.string, is.number, is.boolean, is.plainObject, and is.array return true for matching types and false otherwise
  3. is.nullOrUndefined returns true only for null and undefined
  4. is.nonEmptyString and is.inRange correctly validate string content and numeric boundaries

Files

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

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/%40sindresorhus/is@4.6.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40sindresorhus/is@4.6.0
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:f066a4c7caa15dcc0f1b1e3a9e519a083b4946b80aaa2c770e59b85ba3ae8328","constraints":{"executionContext":"node"},"contract":["is returns the correct type name string for primitives and objects","is.string, is.number, is.boolean, is.plainObject, and is.array return true for matching types and false otherwise","is.nullOrUndefined returns true only for null and undefined","is.nonEmptyString and is.inRange correctly validate string content and numeric boundaries"],"goal":"verify pkg:npm/%40sindresorhus/is@4.6.0","kind":"HOW","packages":["pkg:npm/%40sindresorhus/is@4.6.0"],"schemaVersion":1},"contractCommand":["node","test/contract.js"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40sindresorhus/is@4.6.0"],"schemaVersion":1,"subject":"pkg:npm/%40sindresorhus/is@4.6.0","verifierAdapter":"node-typescript@1"}
package-lock.json
{
  "name": "sample-sindresorhus-is",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-sindresorhus-is",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@sindresorhus/is": "4.6.0"
      }
    },
    "node_modules/@sindresorhus/is": {
      "version": "4.6.0",
      "resolved": "https://registry.npmjs.org/@sindresorhus/is/-/is-4.6.0.tgz",
      "integrity": "sha512-t09vSN3MdfsyCHoFcTRCH/iUtG7OJ0CsjzB8cjAmKc/va/kIgeDI/TxsigdncE/4be734m0cvIYwNaV4i2XqAw==",
      "license": "MIT",
      "engines": {
        "node": ">=10"
      },
      "funding": {
        "url": "https://github.com/sindresorhus/is?sponsor=1"
      }
    }
  }
}
package.json
{
  "name": "sample-sindresorhus-is",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification sample for @sindresorhus/is",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "@sindresorhus/is": "4.6.0"
  },
  "license": "MIT-0"
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/%40sindresorhus/is@4.6.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40sindresorhus/is@4.6.0"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}
src/index.js
const is = require('@sindresorhus/is');

function inspectType(value) {
  return is(value);
}

function isNonEmptyString(value) {
  return is.nonEmptyString(value);
}

function isPositiveInteger(value) {
  return is.integer(value) && is.inRange(value, [1, Infinity]);
}

function isValidConfig(config) {
  return is.plainObject(config) &&
    is.nonEmptyString(config.name) &&
    is.boolean(config.active);
}

module.exports = {
  is,
  inspectType,
  isNonEmptyString,
  isPositiveInteger,
  isValidConfig
};
test/contract.js
const assert = require('node:assert');
const is = require('@sindresorhus/is');
const {
  inspectType,
  isNonEmptyString,
  isPositiveInteger,
  isValidConfig
} = require('../src/index.js');

// 1. is returns the correct type name string for primitives and objects
assert.strictEqual(is('hello'), 'string', 'is("hello") should return "string"');
assert.strictEqual(is(42), 'number', 'is(42) should return "number"');
assert.strictEqual(is(true), 'boolean', 'is(true) should return "boolean"');
assert.strictEqual(is(null), 'null', 'is(null) should return "null"');
assert.strictEqual(is(undefined), 'undefined', 'is(undefined) should return "undefined"');
assert.strictEqual(is({}), 'Object', 'is({}) should return "Object"');
assert.strictEqual(is([1, 2, 3]), 'Array', 'is([]) should return "Array"');
assert.strictEqual(inspectType('test'), 'string', 'inspectType wrapper should return "string"');

// 2. is.string, is.number, is.boolean, is.plainObject, and is.array return true for matching types and false otherwise
assert.strictEqual(is.string('sample'), true, 'is.string("sample") should be true');
assert.strictEqual(is.string(123), false, 'is.string(123) should be false');

assert.strictEqual(is.number(123), true, 'is.number(123) should be true');
assert.strictEqual(is.number('123'), false, 'is.number("123") should be false');

assert.strictEqual(is.boolean(false), true, 'is.boolean(false) should be true');
assert.strictEqual(is.boolean(0), false, 'is.boolean(0) should be false');

assert.strictEqual(is.plainObject({ key: 'val' }), true, 'is.plainObject({}) should be true');
assert.strictEqual(is.plainObject(new Date()), false, 'is.plainObject(Date) should be false');
assert.strictEqual(is.plainObject([]), false, 'is.plainObject([]) should be false');

assert.strictEqual(is.array([1, 2]), true, 'is.array([]) should be true');
assert.strictEqual(is.array({ length: 0 }), false, 'is.array(obj) should be false');

// 3. is.nullOrUndefined returns true only for null and undefined
assert.strictEqual(is.nullOrUndefined(null), true, 'is.nullOrUndefined(null) should be true');
assert.strictEqual(is.nullOrUndefined(undefined), true, 'is.nullOrUndefined(undefined) should be true');
assert.strictEqual(is.nullOrUndefined(false), false, 'is.nullOrUndefined(false) should be false');
assert.strictEqual(is.nullOrUndefined(0), false, 'is.nullOrUndefined(0) should be false');
assert.strictEqual(is.nullOrUndefined(''), false, 'is.nullOrUndefined("") should be false');

// 4. is.nonEmptyString and is.inRange correctly validate string content and numeric boundaries
assert.strictEqual(is.nonEmptyString('hello'), true, 'is.nonEmptyString("hello") should be true');
assert.strictEqual(is.nonEmptyString(''), false, 'is.nonEmptyString("") should be false');
assert.strictEqual(isNonEmptyString('valid'), true, 'isNonEmptyString helper should return true');
assert.strictEqual(isNonEmptyString(''), false, 'isNonEmptyString helper should return false');

assert.strictEqual(is.inRange(5, [1, 10]), true, 'is.inRange(5, [1, 10]) should be true');
assert.strictEqual(is.inRange(15, [1, 10]), false, 'is.inRange(15, [1, 10]) should be false');
assert.strictEqual(isPositiveInteger(10), true, 'isPositiveInteger(10) should be true');
assert.strictEqual(isPositiveInteger(-5), false, 'isPositiveInteger(-5) should be false');
assert.strictEqual(isPositiveInteger(0), false, 'isPositiveInteger(0) should be false');
assert.strictEqual(isPositiveInteger(3.14), false, 'isPositiveInteger(3.14) should be false');

// 5. isValidConfig helper verification
assert.strictEqual(isValidConfig({ name: 'service', active: true }), true, 'valid config should return true');
assert.strictEqual(isValidConfig({ name: '', active: true }), false, 'config with empty name should return false');
assert.strictEqual(isValidConfig({ name: 'service', active: 'yes' }), false, 'config with non-boolean active should return false');
assert.strictEqual(isValidConfig(null), false, 'null config should return false');

console.log('Contract tests passed successfully.');

Origin Seeder

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