fill-range 7.1.1

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/fill-range@7.1.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/fill-range@7.1.1

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:sha256:999567f94b656745de4d22ff87a77a9b987ac3974833fea6c2cd4a9ae41a239b","contract":["fillRange generates ascending and descending numeric ranges with optional step increments","fillRange preserves zero-padding for formatted numeric string ranges","fillRange generates alphabetical character ranges in ascending and descending order","fillRange supports toRegex and stringify options and custom transform functions"],"goal":"verify pkg:npm/fill-range@7.1.1","kind":"HOW","packages":["pkg:npm/fill-range@7.1.1"],"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/fill-range@7.1.1"],"schemaVersion":1,"subject":"pkg:npm/fill-range@7.1.1","verifierAdapter":"node-typescript@1"}

{
  "name": "sample-fill-range",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-fill-range",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "fill-range": "7.1.1"
      }
    },
    "node_modules/fill-range": {
      "version": "7.1.1",
      "resolved": "https://registry.npmjs.org/fill-range/-/fill-range-7.1.1.tgz",
      "integrity": "sha512-YsGpe3WHLK8ZYi4tWDg2Jy3ebRz2rXowDxnld4bkQB00cc/1Zw9AWnC0i9ztDJitivtQvaI9KaLyKrc+hBW0yg==",
      "license": "MIT",
      "dependencies": {
        "to-regex-range": "^5.0.1"
      },
      "engines": {
        "node": ">=8"
      }
    },
    "node_modules/is-number": {
      "version": "7.0.0",
      "resolved": "https://registry.npmjs.org/is-number/-/is-number-7.0.0.tgz",
      "integrity": "sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==",
      "license": "MIT",
      "engines": {
        "node": ">=0.12.0"
      }
    },
    "node_modules/to-regex-range": {
      "version": "5.0.1",
      "resolved": "https://registry.npmjs.org/to-regex-range/-/to-regex-range-5.0.1.tgz",
      "integrity": "sha512-65P7iz6X5yEr1cwcgvQxbbIw7Uk3gOy5dIdtZ4rDveLqhrdJP+Li/Hx6tyK0NEb+2GCyneCMJiGqrADCSNk8sQ==",
      "license": "MIT",
      "dependencies": {
        "is-number": "^7.0.0"
      },
      "engines": {
        "node": ">=8.0"
      }
    }
  }
}

{
  "name": "sample-fill-range",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification sample for fill-range",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "fill-range": "7.1.1"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/fill-range@7.1.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/fill-range@7.1.1"
  ]
}

const fillRange = require('fill-range');

function generateSequence(start, end, step, options) {
  return fillRange(start, end, step, options);
}

module.exports = {
  generateSequence
};

const assert = require('node:assert');
const fillRange = require('fill-range');
const { generateSequence } = require('../src/index.js');

// Contract 1: fillRange generates ascending and descending numeric ranges with optional step increments
assert.deepStrictEqual(fillRange(1, 5), [1, 2, 3, 4, 5], 'ascending numeric range');
assert.deepStrictEqual(fillRange(5, 1), [5, 4, 3, 2, 1], 'descending numeric range');
assert.deepStrictEqual(fillRange(-3, 2), [-3, -2, -1, 0, 1, 2], 'negative numeric range');
assert.deepStrictEqual(fillRange(1, 10, 2), [1, 3, 5, 7, 9], 'numeric range with step increment');
assert.deepStrictEqual(fillRange(10, 2, 2), [10, 8, 6, 4, 2], 'descending numeric range with step');

// Contract 2: fillRange preserves zero-padding for formatted numeric string ranges
assert.deepStrictEqual(fillRange('1', '5'), ['1', '2', '3', '4', '5'], 'string numeric range');
assert.deepStrictEqual(fillRange('01', '05'), ['01', '02', '03', '04', '05'], 'zero-padded 2-digit range');
assert.deepStrictEqual(fillRange('001', '005'), ['001', '002', '003', '004', '005'], 'zero-padded 3-digit range');

// Contract 3: fillRange generates alphabetical character ranges in ascending and descending order
assert.deepStrictEqual(fillRange('a', 'e'), ['a', 'b', 'c', 'd', 'e'], 'ascending letter range');
assert.deepStrictEqual(fillRange('e', 'a'), ['e', 'd', 'c', 'b', 'a'], 'descending letter range');
assert.deepStrictEqual(fillRange('a', 'i', 2), ['a', 'c', 'e', 'g', 'i'], 'letter range with step');
assert.deepStrictEqual(fillRange('A', 'E'), ['A', 'B', 'C', 'D', 'E'], 'uppercase letter range');

// Contract 4: fillRange supports toRegex and stringify options and custom transform functions
assert.strictEqual(fillRange(1, 5, { toRegex: true }), '[1-5]', 'regex range generation');
assert.strictEqual(fillRange('a', 'e', { toRegex: true }), '[a-e]', 'letter regex range generation');
assert.deepStrictEqual(fillRange(1, 3, { stringify: true }), ['1', '2', '3'], 'stringify option');
assert.deepStrictEqual(fillRange(1, 3, (val) => `item_${val}`), ['item_1', 'item_2', 'item_3'], 'custom transform function');

// Wrapper function integration
assert.deepStrictEqual(generateSequence(1, 3), [1, 2, 3], 'wrapper integer sequence');
assert.deepStrictEqual(generateSequence('a', 'c'), ['a', 'b', 'c'], 'wrapper letter sequence');

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