@jest/get-type 30.1.0: 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 @jest/get-type.isPrimitive in pkg:npm/%40jest/get-type@30.1.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40jest/get-type@30.1.0
Demonstrate these symbols/APIs:
  - @jest/get-type.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:sha256:5173e78f4c49df1e84a5f4579c435a9eb5563c2c3932c7663a85fdcfe3021130","contract":["isPrimitive returns true for primitive values including null, undefined, boolean, number, string, symbol, and bigint","isPrimitive returns true for numeric edge cases NaN, Infinity, and empty string","isPrimitive returns false for reference types including plain objects, null-prototype objects, arrays, and functions","isPrimitive returns false for complex standard objects including Date, RegExp, Map, Set, Promise, and Error","isPrimitive returns false for boxed primitive objects created with constructors or Object wrappers"],"goal":"verify @jest/get-type.isPrimitive in pkg:npm/%40jest/get-type@30.1.0","kind":"HOW","packages":["pkg:npm/%40jest/get-type@30.1.0"],"schemaVersion":1,"symbols":["@jest/get-type.isPrimitive"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40jest/get-type@30.1.0"],"schemaVersion":1,"subject":"pkg:npm/%40jest/get-type@30.1.0","symbols":["@jest/get-type.isPrimitive"],"verifierAdapter":"node-typescript@1"}

import { isPrimitive as jestIsPrimitive } from '@jest/get-type';

/**
 * Determines whether the given value is a JavaScript primitive.
 * Primitives in JavaScript include null, undefined, string, number, boolean, symbol, and bigint.
 *
 * @param {unknown} value - Value to check.
 * @returns {boolean} True if value is a primitive, false otherwise.
 */
export function isPrimitive(value) {
  return jestIsPrimitive(value);
}

/**
 * Filters an array of values, returning only the primitive values.
 *
 * @param {unknown[]} values - Array of values to filter.
 * @returns {unknown[]} Array containing only primitive values.
 */
export function filterPrimitives(values) {
  return values.filter(jestIsPrimitive);
}

/**
 * Filters an array of values, returning only the non-primitive (object) values.
 *
 * @param {unknown[]} values - Array of values to filter.
 * @returns {unknown[]} Array containing only non-primitive values.
 */
export function filterNonPrimitives(values) {
  return values.filter((val) => !jestIsPrimitive(val));
}

{
  "name": "sample-jest-get-type-is-primitive",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-jest-get-type-is-primitive",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@jest/get-type": "30.1.0"
      }
    },
    "node_modules/@jest/get-type": {
      "version": "30.1.0",
      "resolved": "https://registry.npmjs.org/@jest/get-type/-/get-type-30.1.0.tgz",
      "integrity": "sha512-eMbZE2hUnx1WV0pmURZY9XoXPkUYjpc55mb0CrhtdWLtzMQPFvu/rZkTLZFTsdaVQa+Tr4eWAteqcUzoawq/uA==",
      "license": "MIT",
      "engines": {
        "node": "^18.14.0 || ^20.0.0 || ^22.0.0 || >=24.0.0"
      }
    }
  }
}

{
  "name": "sample-jest-get-type-is-primitive",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "@jest/get-type": "30.1.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @jest/get-type.isPrimitive in pkg:npm/%40jest/get-type@30.1.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40jest/get-type@30.1.0"
  ],
  "symbols": [
    "@jest/get-type.isPrimitive"
  ]
}

import assert from 'node:assert/strict';
import { isPrimitive as jestIsPrimitive } from '@jest/get-type';
import { isPrimitive, filterPrimitives, filterNonPrimitives } from '../index.mjs';

// 1. isPrimitive returns true for primitive values including null, undefined, boolean, number, string, symbol, and bigint
assert.strictEqual(isPrimitive(null), true);
assert.strictEqual(isPrimitive(undefined), true);
assert.strictEqual(isPrimitive(true), true);
assert.strictEqual(isPrimitive(false), true);
assert.strictEqual(isPrimitive(0), true);
assert.strictEqual(isPrimitive(42), true);
assert.strictEqual(isPrimitive(-100), true);
assert.strictEqual(isPrimitive(3.14159), true);
assert.strictEqual(isPrimitive('hello'), true);
assert.strictEqual(isPrimitive(Symbol('token')), true);
assert.strictEqual(isPrimitive(Symbol.iterator), true);
assert.strictEqual(isPrimitive(0n), true);
assert.strictEqual(isPrimitive(9007199254740991n), true);

// 2. isPrimitive returns true for numeric edge cases NaN, Infinity, and empty string
assert.strictEqual(isPrimitive(NaN), true);
assert.strictEqual(isPrimitive(Infinity), true);
assert.strictEqual(isPrimitive(-Infinity), true);
assert.strictEqual(isPrimitive(''), true);

// 3. isPrimitive returns false for reference types including plain objects, null-prototype objects, arrays, and functions
assert.strictEqual(isPrimitive({}), false);
assert.strictEqual(isPrimitive({ key: 'val' }), false);
assert.strictEqual(isPrimitive(Object.create(null)), false);
assert.strictEqual(isPrimitive([]), false);
assert.strictEqual(isPrimitive([1, 2, 3]), false);
assert.strictEqual(isPrimitive(() => {}), false);
assert.strictEqual(isPrimitive(function named() {}), false);
assert.strictEqual(isPrimitive(class MyClass {}), false);

// 4. isPrimitive returns false for complex standard objects including Date, RegExp, Map, Set, Promise, and Error
assert.strictEqual(isPrimitive(new Date()), false);
assert.strictEqual(isPrimitive(/regex/gi), false);
assert.strictEqual(isPrimitive(new RegExp('pattern')), false);
assert.strictEqual(isPrimitive(new Map()), false);
assert.strictEqual(isPrimitive(new Set()), false);
assert.strictEqual(isPrimitive(new WeakMap()), false);
assert.strictEqual(isPrimitive(new WeakSet()), false);
assert.strictEqual(isPrimitive(Promise.resolve()), false);
assert.strictEqual(isPrimitive(new Error('failure')), false);

// 5. isPrimitive returns false for boxed primitive objects created with constructors or Object wrappers
assert.strictEqual(isPrimitive(new Number(42)), false);
assert.strictEqual(isPrimitive(new String('boxed')), false);
assert.strictEqual(isPrimitive(new Boolean(true)), false);
assert.strictEqual(isPrimitive(Object(Symbol('boxed-sym'))), false);
assert.strictEqual(isPrimitive(Object(100n)), false);

// Helper functions contract verification
const mixed = [1, 'two', { id: 3 }, null, [4], 5n, false, new Date()];
assert.deepStrictEqual(filterPrimitives(mixed), [1, 'two', null, 5n, false]);
assert.strictEqual(filterNonPrimitives(mixed).length, 3);
assert.deepStrictEqual(filterNonPrimitives(mixed)[0], { id: 3 });
assert.deepStrictEqual(filterNonPrimitives(mixed)[1], [4]);
assert.ok(filterNonPrimitives(mixed)[2] instanceof Date);

// Direct package export equivalence
assert.strictEqual(jestIsPrimitive(null), true);
assert.strictEqual(jestIsPrimitive({}), false);

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