ansi-styles 6.2.3: modifier

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 ansi-styles.modifier in pkg:npm/ansi-styles@6.2.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/ansi-styles@6.2.3
Demonstrate these symbols/APIs:
  - ansi-styles.modifier

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:ff839b2aa472de06209ae63b8207f0ceaa1635192ff1cdacc3b046db11c41d6f","contract":["modifier is an object containing standard text style modifiers with open and close ANSI escape sequences","modifier includes reset, bold, dim, italic, underline, overline, inverse, hidden, and strikethrough modifiers","every modifier style has valid opening and closing escape codes that reset the corresponding style","isValidModifier verifies whether a given modifier name exists in modifier","applyModifier wraps text in the opening and closing ANSI escape sequences for a specified modifier"],"goal":"verify ansi-styles.modifier in pkg:npm/ansi-styles@6.2.3","kind":"HOW","packages":["pkg:npm/ansi-styles@6.2.3"],"schemaVersion":1,"symbols":["ansi-styles.modifier"]},"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/ansi-styles@6.2.3"],"schemaVersion":1,"subject":"pkg:npm/ansi-styles@6.2.3","symbols":["ansi-styles.modifier"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-ansi-styles-modifier",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-ansi-styles-modifier",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "ansi-styles": "6.2.3"
      }
    },
    "node_modules/ansi-styles": {
      "version": "6.2.3",
      "resolved": "https://registry.npmjs.org/ansi-styles/-/ansi-styles-6.2.3.tgz",
      "integrity": "sha512-4Dj6M28JB+oAH8kFkTLUo+a2jwOFkuqb3yucU0CANcRRUbxS0cP0nZYCGjcc3BNXwRIsUVmDGgzawme7zvJHvg==",
      "license": "MIT",
      "engines": {
        "node": ">=12"
      },
      "funding": {
        "url": "https://github.com/chalk/ansi-styles?sponsor=1"
      }
    }
  }
}

{
  "name": "sample-ansi-styles-modifier",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification for ansi-styles modifier",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "ansi-styles": "6.2.3"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify ansi-styles.modifier in pkg:npm/ansi-styles@6.2.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/ansi-styles@6.2.3"
  ],
  "symbols": [
    "ansi-styles.modifier"
  ]
}

const ansiStylesModule = require('ansi-styles');

const ansiStyles = ansiStylesModule.default || ansiStylesModule;
const modifier = ansiStyles.modifier;
const modifierNames = ansiStylesModule.modifierNames || ansiStyles.modifierNames;

/**
 * Returns the modifier map from ansi-styles.
 * @returns {Record<string, { open: string, close: string }>}
 */
function getModifiers() {
  return modifier || ansiStyles.modifier;
}

/**
 * Returns the list of supported modifier names.
 * @returns {string[]}
 */
function getModifierNames() {
  return modifierNames || Object.keys(getModifiers());
}

/**
 * Checks if a given string is a valid modifier name in ansi-styles.
 * @param {string} name
 * @returns {boolean}
 */
function isValidModifier(name) {
  const modifiers = getModifiers();
  return typeof name === 'string' && name in modifiers;
}

/**
 * Retrieves the open and close ANSI escape sequences for a modifier name.
 * @param {string} name
 * @returns {{ open: string, close: string }}
 */
function getModifierCodes(name) {
  if (!isValidModifier(name)) {
    throw new Error(`Invalid modifier name: ${name}`);
  }
  const modifiers = getModifiers();
  return {
    open: modifiers[name].open,
    close: modifiers[name].close,
  };
}

/**
 * Wraps text in the specified modifier's opening and closing ANSI escape codes.
 * @param {string} text
 * @param {string} name
 * @returns {string}
 */
function applyModifier(text, name) {
  const { open, close } = getModifierCodes(name);
  return `${open}${text}${close}`;
}

module.exports = {
  ansiStyles,
  modifier: ansiStyles.modifier,
  modifierNames,
  getModifiers,
  getModifierNames,
  isValidModifier,
  getModifierCodes,
  applyModifier,
};

const assert = require('node:assert');
const {
  ansiStyles,
  modifier,
  modifierNames,
  getModifiers,
  getModifierNames,
  isValidModifier,
  getModifierCodes,
  applyModifier,
} = require('../src/index.js');

// 1. modifier is an object containing standard text style modifiers with open and close ANSI escape sequences
assert(modifier && typeof modifier === 'object', 'modifier must be an object');
assert.deepStrictEqual(getModifiers(), ansiStyles.modifier);

for (const [name, style] of Object.entries(modifier)) {
  assert(typeof style.open === 'string' && style.open.startsWith('\u001B['), `${name} open code must start with ANSI escape sequence`);
  assert(typeof style.close === 'string' && style.close.startsWith('\u001B['), `${name} close code must start with ANSI escape sequence`);
  assert(style.open.endsWith('m'), `${name} open code must end with 'm'`);
  assert(style.close.endsWith('m'), `${name} close code must end with 'm'`);
}

// 2. modifier includes reset, bold, dim, italic, underline, overline, inverse, hidden, and strikethrough modifiers
const expectedModifiers = [
  'reset',
  'bold',
  'dim',
  'italic',
  'underline',
  'overline',
  'inverse',
  'hidden',
  'strikethrough',
];

for (const name of expectedModifiers) {
  assert(name in modifier, `Missing modifier: ${name}`);
  assert(getModifierNames().includes(name), `Missing modifier in modifierNames: ${name}`);
}

// 3. every modifier style has valid opening and closing escape codes that reset the corresponding style
assert.strictEqual(modifier.reset.open, '\u001B[0m');
assert.strictEqual(modifier.reset.close, '\u001B[0m');

assert.strictEqual(modifier.bold.open, '\u001B[1m');
assert.strictEqual(modifier.bold.close, '\u001B[22m');

assert.strictEqual(modifier.dim.open, '\u001B[2m');
assert.strictEqual(modifier.dim.close, '\u001B[22m');

assert.strictEqual(modifier.italic.open, '\u001B[3m');
assert.strictEqual(modifier.italic.close, '\u001B[23m');

assert.strictEqual(modifier.underline.open, '\u001B[4m');
assert.strictEqual(modifier.underline.close, '\u001B[24m');

assert.strictEqual(modifier.overline.open, '\u001B[53m');
assert.strictEqual(modifier.overline.close, '\u001B[55m');

assert.strictEqual(modifier.inverse.open, '\u001B[7m');
assert.strictEqual(modifier.inverse.close, '\u001B[27m');

assert.strictEqual(modifier.hidden.open, '\u001B[8m');
assert.strictEqual(modifier.hidden.close, '\u001B[28m');

assert.strictEqual(modifier.strikethrough.open, '\u001B[9m');
assert.strictEqual(modifier.strikethrough.close, '\u001B[29m');

// Also test direct access on ansiStyles root matches ansiStyles.modifier
for (const name of expectedModifiers) {
  assert.deepStrictEqual(ansiStyles[name], modifier[name], `ansiStyles.${name} must match modifier.${name}`);
}

// 4. isValidModifier verifies whether a given modifier name exists in modifier
assert.strictEqual(isValidModifier('bold'), true);
assert.strictEqual(isValidModifier('italic'), true);
assert.strictEqual(isValidModifier('underline'), true);
assert.strictEqual(isValidModifier('overline'), true);
assert.strictEqual(isValidModifier('inverse'), true);
assert.strictEqual(isValidModifier('hidden'), true);
assert.strictEqual(isValidModifier('strikethrough'), true);
assert.strictEqual(isValidModifier('reset'), true);
assert.strictEqual(isValidModifier('color'), false);
assert.strictEqual(isValidModifier('red'), false);
assert.strictEqual(isValidModifier('unknownModifier'), false);
assert.strictEqual(isValidModifier(''), false);
assert.strictEqual(isValidModifier(null), false);

// 5. applyModifier wraps text in the opening and closing ANSI escape sequences for a specified modifier
const sampleText = 'Sample Text';
assert.strictEqual(applyModifier(sampleText, 'bold'), `\u001B[1m${sampleText}\u001B[22m`);
assert.strictEqual(applyModifier(sampleText, 'italic'), `\u001B[3m${sampleText}\u001B[23m`);
assert.strictEqual(applyModifier(sampleText, 'underline'), `\u001B[4m${sampleText}\u001B[24m`);
assert.strictEqual(applyModifier(sampleText, 'overline'), `\u001B[53m${sampleText}\u001B[55m`);
assert.strictEqual(applyModifier(sampleText, 'inverse'), `\u001B[7m${sampleText}\u001B[27m`);
assert.strictEqual(applyModifier(sampleText, 'hidden'), `\u001B[8m${sampleText}\u001B[28m`);
assert.strictEqual(applyModifier(sampleText, 'strikethrough'), `\u001B[9m${sampleText}\u001B[29m`);
assert.strictEqual(applyModifier(sampleText, 'reset'), `\u001B[0m${sampleText}\u001B[0m`);

assert.throws(() => {
  applyModifier(sampleText, 'invalidModifier');
}, /Invalid modifier name: invalidModifier/);

console.log('All contract assertions passed successfully.');