is-arrayish 0.2.1: isArrayish

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 isArrayish in pkg:npm/is-arrayish@0.2.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/is-arrayish@0.2.1
Demonstrate these symbols/APIs:
  - isArrayish
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.

{"case":{"caseId":"case:sha256:20beb4625af8af4843a41a8f38dc5aa40b9d8123e6bb9979c89fc34af7f5af1f","constraints":{"executionContext":"node"},"contract":["isArrayish returns true for standard array literals and Array instances","isArrayish returns true for objects with a non-negative length property and a splice function","isArrayish returns false for null, undefined, and falsy primitives","isArrayish returns false for plain objects without length or splice methods","isArrayish returns false for strings and primitive values","isArrayish returns false for objects where length is negative or splice is not a function"],"goal":"verify isArrayish in pkg:npm/is-arrayish@0.2.1","kind":"HOW","packages":["pkg:npm/is-arrayish@0.2.1"],"schemaVersion":1,"symbols":["isArrayish"]},"contractCommand":["node","test/contract.mjs"],"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/is-arrayish@0.2.1"],"schemaVersion":1,"subject":"pkg:npm/is-arrayish@0.2.1","symbols":["isArrayish"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-is-arrayish",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-is-arrayish",
      "version": "1.0.0",
      "dependencies": {
        "is-arrayish": "0.2.1"
      }
    },
    "node_modules/is-arrayish": {
      "version": "0.2.1",
      "resolved": "https://registry.npmjs.org/is-arrayish/-/is-arrayish-0.2.1.tgz",
      "integrity": "sha512-zz06S8t0ozoDXMG+ube26zeCTNXcKIPJZJi8hBrF4idCLms4CG9QtK7qBl1boi5ODzFpjswb5JPmHCbMpjaYzg==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-is-arrayish",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "dependencies": {
    "is-arrayish": "0.2.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify isArrayish in pkg:npm/is-arrayish@0.2.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/is-arrayish@0.2.1"
  ],
  "symbols": [
    "isArrayish"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

import assert from 'node:assert/strict';
import isArrayish from 'is-arrayish';

// 1. isArrayish returns true for standard array literals and Array instances
{
  assert.equal(isArrayish([]), true);
  assert.equal(isArrayish([1, 2, 3]), true);
  assert.equal(isArrayish(new Array(5)), true);
}

// 2. isArrayish returns true for objects with a non-negative length property and a splice function
{
  const customArrayish = {
    length: 0,
    splice: function () {},
  };
  assert.equal(isArrayish(customArrayish), true);

  const populatedArrayish = {
    0: 'hello',
    1: 'world',
    length: 2,
    splice: Array.prototype.splice,
  };
  assert.equal(isArrayish(populatedArrayish), true);
}

// 3. isArrayish returns false for null, undefined, and falsy primitives
{
  assert.equal(isArrayish(null), false);
  assert.equal(isArrayish(undefined), false);
  assert.equal(isArrayish(0), false);
  assert.equal(isArrayish(''), false);
  assert.equal(isArrayish(false), false);
  assert.equal(isArrayish(NaN), false);
}

// 4. isArrayish returns false for plain objects without length or splice methods
{
  assert.equal(isArrayish({}), false);
  assert.equal(isArrayish({ a: 1, b: 2 }), false);
  assert.equal(isArrayish({ length: 0 }), false);
  assert.equal(isArrayish({ length: 5 }), false);
  assert.equal(isArrayish({ splice: function () {} }), false);
}

// 5. isArrayish returns false for strings and primitive values
{
  assert.equal(isArrayish('string'), false);
  assert.equal(isArrayish(123), false);
  assert.equal(isArrayish(true), false);
  assert.equal(isArrayish(Symbol('test')), false);
  assert.equal(isArrayish(BigInt(10)), false);
}

// 6. isArrayish returns false for objects where length is negative or splice is not a function
{
  const negativeLength = {
    length: -1,
    splice: function () {},
  };
  assert.equal(isArrayish(negativeLength), false);

  const nonFunctionSplice = {
    length: 2,
    splice: 'not a function',
  };
  assert.equal(isArrayish(nonFunctionSplice), false);
}