CodeSampleX

Sample

yargs 17.7.3

Verified sample for npm yargs 17.7.3. The contract ran on node 22 · linux alpine/x64 · docker and passed: yargs parses command line options with types…

sha256:9fd39498cf52b547cca7fe74c692436a6224f7d194ac920d800c658774dcf453

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
1
Signing keys that built it
1
Declared environment linux 24 · ubuntu · glibc 2.39 x64 npm

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@1node:22-alpine@sha256:c610fcdfb1d5…
2026-08-23

Case

HOW
Goal
verify pkg:npm/yargs@17.7.3
Packages
Created
2026-08-23T08:18:01Z

Contract

  1. yargs parses command line options with types, aliases, defaults, and descriptions
  2. yargs enforces option requirements with demandOption and choices validation
  3. yargs supports command routing with positional arguments and handler execution
  4. yargs supports type coercion and custom validation via coerce and check
  5. yargs provides parseSync and parse to synchronously or asynchronously extract parsed arguments

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/yargs@17.7.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/yargs@17.7.3

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
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package-lock.json
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package.json
{
  "name": "sample-yargs",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification sample for yargs",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "yargs": "17.7.3"
  },
  "license": "MIT-0"
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/yargs@17.7.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/yargs@17.7.3"
  ]
}
src/index.js
const yargs = require('yargs/yargs');

function createParser(args) {
  return yargs(args)
    .exitProcess(false)
    .showHelpOnFail(false)
    .fail((msg, err) => {
      throw err || new Error(msg);
    });
}

function parseCliOptions(args) {
  return createParser(args)
    .option('port', {
      alias: 'p',
      type: 'number',
      default: 8080,
      describe: 'Port number to listen on'
    })
    .option('host', {
      alias: 'h',
      type: 'string',
      default: 'localhost',
      describe: 'Hostname to bind to'
    })
    .option('verbose', {
      alias: 'v',
      type: 'boolean',
      default: false,
      describe: 'Enable verbose logging'
    })
    .parseSync();
}

function parseWithCommands(args) {
  let executedCommand = null;
  let commandArgs = null;

  const parser = createParser(args)
    .command(
      'serve <dir>',
      'Start a file server',
      (y) => {
        return y.positional('dir', {
          type: 'string',
          describe: 'Directory to serve'
        }).option('port', {
          alias: 'p',
          type: 'number',
          default: 3000
        });
      },
      (argv) => {
        executedCommand = 'serve';
        commandArgs = argv;
      }
    )
    .command(
      'build [entry]',
      'Build project assets',
      (y) => {
        return y.positional('entry', {
          type: 'string',
          default: 'index.js'
        }).option('minify', {
          type: 'boolean',
          default: false
        });
      },
      (argv) => {
        executedCommand = 'build';
        commandArgs = argv;
      }
    );

  const argv = parser.parseSync();
  return { argv, executedCommand, commandArgs };
}

function parseWithValidation(args) {
  return createParser(args)
    .option('format', {
      type: 'string',
      choices: ['json', 'yaml', 'text'],
      demandOption: true
    })
    .option('count', {
      type: 'number',
      coerce: (val) => {
        const num = Number(val);
        if (isNaN(num) || num <= 0) {
          throw new Error('count must be a positive integer');
        }
        return num;
      }
    })
    .check((argv) => {
      if (argv.format === 'yaml' && argv.count > 100) {
        throw new Error('YAML format is limited to count <= 100');
      }
      return true;
    })
    .parseSync();
}

module.exports = {
  createParser,
  parseCliOptions,
  parseWithCommands,
  parseWithValidation
};
test/contract.js
const assert = require('node:assert');
const yargs = require('yargs/yargs');
const {
  createParser,
  parseCliOptions,
  parseWithCommands,
  parseWithValidation
} = require('../src/index.js');

// 1. yargs parses command line options with types, aliases, defaults, and descriptions
{
  const defaultRes = parseCliOptions([]);
  assert.strictEqual(defaultRes.port, 8080, 'port should default to 8080');
  assert.strictEqual(defaultRes.host, 'localhost', 'host should default to localhost');
  assert.strictEqual(defaultRes.verbose, false, 'verbose should default to false');

  const customRes = parseCliOptions(['-p', '9000', '--host', '127.0.0.1', '-v']);
  assert.strictEqual(customRes.port, 9000, 'port should be parsed from alias -p');
  assert.strictEqual(customRes.p, 9000, 'alias p should match port value');
  assert.strictEqual(customRes.host, '127.0.0.1', 'host should be parsed from flag');
  assert.strictEqual(customRes.verbose, true, 'verbose should be true from alias -v');
  assert.strictEqual(customRes.v, true, 'alias v should match verbose value');
}

// 2. yargs enforces option requirements with demandOption and choices validation
{
  assert.throws(
    () => parseWithValidation([]),
    (err) => err.message.includes('Missing required argument: format'),
    'should fail when demanded option format is missing'
  );

  assert.throws(
    () => parseWithValidation(['--format', 'xml']),
    (err) => err.message.includes('Invalid values') && err.message.includes('format'),
    'should fail when value is not in allowed choices'
  );

  const validRes = parseWithValidation(['--format', 'json']);
  assert.strictEqual(validRes.format, 'json', 'valid format option should parse correctly');
}

// 3. yargs supports command routing with positional arguments and handler execution
{
  const serveRes = parseWithCommands(['serve', './public', '--port', '4000']);
  assert.strictEqual(serveRes.executedCommand, 'serve', 'serve command handler should have executed');
  assert.strictEqual(serveRes.commandArgs.dir, './public', 'positional argument dir should match');
  assert.strictEqual(serveRes.commandArgs.port, 4000, 'command option port should be 4000');

  const buildRes = parseWithCommands(['build', '--minify']);
  assert.strictEqual(buildRes.executedCommand, 'build', 'build command handler should have executed');
  assert.strictEqual(buildRes.commandArgs.entry, 'index.js', 'default positional entry should be index.js');
  assert.strictEqual(buildRes.commandArgs.minify, true, 'minify flag should be true');
}

// 4. yargs supports type coercion and custom validation via coerce and check
{
  assert.throws(
    () => parseWithValidation(['--format', 'json', '--count', '-5']),
    (err) => err.message.includes('count must be a positive integer'),
    'coerce should reject negative numbers'
  );

  assert.throws(
    () => parseWithValidation(['--format', 'yaml', '--count', '150']),
    (err) => err.message.includes('YAML format is limited to count <= 100'),
    'custom check should reject count > 100 for yaml format'
  );

  const validCustom = parseWithValidation(['--format', 'yaml', '--count', '42']);
  assert.strictEqual(validCustom.count, 42, 'count should be coerced to integer 42');
  assert.strictEqual(validCustom.format, 'yaml', 'format should be yaml');
}

// 5. yargs provides parseSync and parse to synchronously or asynchronously extract parsed arguments
{
  const syncArgv = createParser(['--debug', 'true'])
    .option('debug', { type: 'boolean' })
    .parseSync();
  assert.strictEqual(syncArgv.debug, true, 'parseSync should synchronously return argv');

  let asyncResult = null;
  createParser(['--timeout', '500'])
    .option('timeout', { type: 'number' })
    .parse(['--timeout', '500'], (err, argv, output) => {
      assert.strictEqual(err, null, 'parse callback error should be null');
      asyncResult = argv;
    });
  assert.notStrictEqual(asyncResult, null, 'asyncResult should be populated');
  assert.strictEqual(asyncResult.timeout, 500, 'parsed timeout should be 500');
}

console.log('All yargs contract tests passed successfully.');

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