@vitest/utils 4.1.10: isPrimitive

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 @vitest/utils.isPrimitive in pkg:npm/%40vitest/utils@4.1.10
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40vitest/utils@4.1.10
Demonstrate these symbols/APIs:
  - @vitest/utils.isPrimitive

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:aa7a428d500ab20d350ff51faab803e63f4da8f1473025660a4de2b1d4c84bb6","contract":["isPrimitive returns true for null and undefined","isPrimitive returns true for string, number, boolean, symbol, and bigint primitives","isPrimitive treats special numeric values NaN and positive or negative Infinity as primitives","isPrimitive returns false for plain objects, arrays, and null-prototype objects","isPrimitive returns false for functions, async functions, and class constructors","isPrimitive returns false for boxed primitive instances and built-in object instances like Date and RegExp"],"goal":"verify @vitest/utils.isPrimitive in pkg:npm/%40vitest/utils@4.1.10","kind":"HOW","packages":["pkg:npm/%40vitest/utils@4.1.10"],"schemaVersion":1,"symbols":["@vitest/utils.isPrimitive"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","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/%40vitest/utils@4.1.10"],"schemaVersion":1,"subject":"pkg:npm/%40vitest/utils@4.1.10","symbols":["@vitest/utils.isPrimitive"],"verifierAdapter":"node-typescript@1"}

import { isPrimitive } from '@vitest/utils/helpers';

export { isPrimitive };

export function checkPrimitive(value) {
  return isPrimitive(value);
}

{
  "name": "sample-vitest-utils-isprimitive",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-vitest-utils-isprimitive",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@vitest/utils": "4.1.10"
      }
    },
    "node_modules/@vitest/pretty-format": {
      "version": "4.1.10",
      "resolved": "https://registry.npmjs.org/@vitest/pretty-format/-/pretty-format-4.1.10.tgz",
      "integrity": "sha512-W1HsjSH4MXQ9YfmmhLAoIYf1HRfekQCGngeIgcei6MP5QQGWUe0gkopdZQaVCFO+JDJMrAJGwa5pRpNpvy4P8Q==",
      "license": "MIT",
      "dependencies": {
        "tinyrainbow": "^3.1.0"
      },
      "funding": {
        "url": "https://opencollective.com/vitest"
      }
    },
    "node_modules/@vitest/utils": {
      "version": "4.1.10",
      "resolved": "https://registry.npmjs.org/@vitest/utils/-/utils-4.1.10.tgz",
      "integrity": "sha512-fy9am/HWxbaGt/Sawrp90vt6Y6jQwf1RX77cz3uwoJwJVMli/e1IEwRPnMNJ7vKfPTwo0diXifkpPvwH9v7nGA==",
      "license": "MIT",
      "dependencies": {
        "@vitest/pretty-format": "4.1.10",
        "convert-source-map": "^2.0.0",
        "tinyrainbow": "^3.1.0"
      },
      "funding": {
        "url": "https://opencollective.com/vitest"
      }
    },
    "node_modules/convert-source-map": {
      "version": "2.0.0",
      "resolved": "https://registry.npmjs.org/convert-source-map/-/convert-source-map-2.0.0.tgz",
      "integrity": "sha512-Kvp459HrV2FEJ1CAsi1Ku+MY3kasH19TFykTz2xWmMeq6bk2NU3XXvfJ+Q61m0xktWwt+1HSYf3JZsTms3aRJg==",
      "license": "MIT"
    },
    "node_modules/tinyrainbow": {
      "version": "3.1.1",
      "resolved": "https://registry.npmjs.org/tinyrainbow/-/tinyrainbow-3.1.1.tgz",
      "integrity": "sha512-yau8yJdTt989Mm0Bd/236QnzEiPf2xLLTqUZRUJOo/3CB078LSwzei343DgtJVmfJKJE3TMINY1u42SQsP6mXw==",
      "license": "MIT",
      "engines": {
        "node": ">=14.0.0"
      }
    }
  }
}

{
  "name": "sample-vitest-utils-isprimitive",
  "version": "1.0.0",
  "description": "Clean-room verification sample for @vitest/utils.isPrimitive",
  "type": "module",
  "license": "MIT-0",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "@vitest/utils": "4.1.10"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @vitest/utils.isPrimitive in pkg:npm/%40vitest/utils@4.1.10",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40vitest/utils@4.1.10"
  ],
  "symbols": [
    "@vitest/utils.isPrimitive"
  ]
}

import assert from 'node:assert/strict';
import { isPrimitive } from '@vitest/utils/helpers';
import { checkPrimitive } from '../index.mjs';

// 1. isPrimitive returns true for null and undefined
{
  assert.equal(isPrimitive(null), true);
  assert.equal(isPrimitive(undefined), true);
  assert.equal(checkPrimitive(null), true);
  assert.equal(checkPrimitive(undefined), true);
}

// 2. isPrimitive returns true for string, number, boolean, symbol, and bigint primitives
{
  assert.equal(isPrimitive(''), true);
  assert.equal(isPrimitive('vitest'), true);
  assert.equal(isPrimitive(0), true);
  assert.equal(isPrimitive(-42), true);
  assert.equal(isPrimitive(3.14159), true);
  assert.equal(isPrimitive(true), true);
  assert.equal(isPrimitive(false), true);
  assert.equal(isPrimitive(Symbol('token')), true);
  assert.equal(isPrimitive(Symbol.for('key')), true);
  assert.equal(isPrimitive(0n), true);
  assert.equal(isPrimitive(9007199254740991n), true);
}

// 3. isPrimitive treats special numeric values NaN and positive or negative Infinity as primitives
{
  assert.equal(isPrimitive(NaN), true);
  assert.equal(isPrimitive(Infinity), true);
  assert.equal(isPrimitive(-Infinity), true);
}

// 4. isPrimitive returns false for plain objects, arrays, and null-prototype objects
{
  assert.equal(isPrimitive({}), false);
  assert.equal(isPrimitive({ key: 'value' }), false);
  assert.equal(isPrimitive([]), false);
  assert.equal(isPrimitive([1, 2, 3]), false);
  assert.equal(isPrimitive(Object.create(null)), false);
}

// 5. isPrimitive returns false for functions, async functions, and class constructors
{
  assert.equal(isPrimitive(() => {}), false);
  assert.equal(isPrimitive(function testFn() {}), false);
  assert.equal(isPrimitive(async () => {}), false);
  assert.equal(isPrimitive(class TestClass {}), false);
}

// 6. isPrimitive returns false for boxed primitive instances and built-in object instances like Date and RegExp
{
  assert.equal(isPrimitive(new Number(42)), false);
  assert.equal(isPrimitive(new String('boxed')), false);
  assert.equal(isPrimitive(new Boolean(true)), false);
  assert.equal(isPrimitive(Object(Symbol('boxed'))), false);
  assert.equal(isPrimitive(Object(123n)), false);
  assert.equal(isPrimitive(new Date()), false);
  assert.equal(isPrimitive(/vitest-utils/i), false);
  assert.equal(isPrimitive(new Map()), false);
  assert.equal(isPrimitive(new Set()), false);
  assert.equal(isPrimitive(Promise.resolve()), false);
}

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