y18n 5.0.8

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/y18n@5.0.8
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/y18n@5.0.8

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:sha256:1267912fe56fcab5f9d62ec7e42f188049f2d6af0637201cfb5dd18bef845177","contract":["createI18n initializes y18n instance and translates strings with placeholder substitution","y18n supports tagged template literal invocation via __","translatePlural handles singular and plural counts with placeholder interpolation","changeLocale and getLocale update and inspect active locale","addTranslations injects key-value translation mappings dynamically"],"goal":"verify pkg:npm/y18n@5.0.8","kind":"HOW","packages":["pkg:npm/y18n@5.0.8"],"schemaVersion":1},"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/y18n@5.0.8"],"schemaVersion":1,"subject":"pkg:npm/y18n@5.0.8","verifierAdapter":"node-typescript@1"}

import y18n from 'y18n';

export function createI18n(options = {}) {
  return y18n({
    directory: options.directory || './locales',
    locale: options.locale || 'en',
    updateFiles: options.updateFiles ?? false,
    fallbackToLanguage: options.fallbackToLanguage ?? true
  });
}

export function translate(instance, str, ...args) {
  return instance.__(str, ...args);
}

export function translatePlural(instance, singular, plural, count, ...args) {
  return instance.__n(singular, plural, count, ...args);
}

export function changeLocale(instance, locale) {
  instance.setLocale(locale);
  return instance.getLocale();
}

export function addTranslations(instance, translations) {
  instance.updateLocale(translations);
}

export default y18n;

{
  "name": "sample-y18n-verify",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-y18n-verify",
      "version": "1.0.0",
      "dependencies": {
        "y18n": "5.0.8"
      }
    },
    "node_modules/y18n": {
      "version": "5.0.8",
      "resolved": "https://registry.npmjs.org/y18n/-/y18n-5.0.8.tgz",
      "integrity": "sha512-0pfFzegeDWJHJIAmTLRP2DwHjdF5s7jo9tuztdQxAhINCdvS+3nGINqPd00AphqJR/0LhANUS6/+7SCb98YOfA==",
      "license": "ISC",
      "engines": {
        "node": ">=10"
      }
    }
  }
}

{
  "name": "sample-y18n-verify",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "dependencies": {
    "y18n": "5.0.8"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/y18n@5.0.8",
  "kind": "HOW",
  "packages": [
    "pkg:npm/y18n@5.0.8"
  ]
}

import assert from 'node:assert/strict';
import {
  createI18n,
  translate,
  translatePlural,
  changeLocale,
  addTranslations
} from '../index.mjs';

// 1. assert createI18n initializes y18n instance and translates strings with placeholder substitution
{
  const i18n = createI18n({ locale: 'en' });
  const result = translate(i18n, 'Hello %s, you have %d messages', 'User', 3);
  assert.strictEqual(result, 'Hello User, you have 3 messages');
}

// 2. assert y18n supports tagged template literal invocation via __
{
  const i18n = createI18n({ locale: 'en' });
  const name = 'Alice';
  const count = 42;
  const result = i18n.__`Welcome ${name}! Score: ${count}`;
  assert.strictEqual(result, 'Welcome Alice! Score: 42');
}

// 3. assert translatePlural (__n) handles singular and plural counts with placeholder interpolation
{
  const i18n = createI18n({ locale: 'en' });
  const singular = translatePlural(i18n, '%d item selected', '%d items selected', 1);
  assert.strictEqual(singular, '1 item selected');

  const plural = translatePlural(i18n, '%d item selected', '%d items selected', 5);
  assert.strictEqual(plural, '5 items selected');

  const customArg = translatePlural(i18n, '%d file (%s)', '%d files (%s)', 2, 'compressed');
  assert.strictEqual(customArg, '2 files (compressed)');
}

// 4. assert changeLocale and getLocale update and inspect active locale
{
  const i18n = createI18n({ locale: 'en' });
  assert.strictEqual(i18n.getLocale(), 'en');
  const updated = changeLocale(i18n, 'fr');
  assert.strictEqual(updated, 'fr');
  assert.strictEqual(i18n.getLocale(), 'fr');
}

// 5. assert addTranslations (updateLocale) injects key-value translation mappings dynamically
{
  const i18n = createI18n({ locale: 'es' });
  addTranslations(i18n, {
    'Goodbye %s': '¡Adiós %s!',
    'Hello %s': '¡Hola %s!'
  });
  const greeting = translate(i18n, 'Hello %s', 'Amigo');
  assert.strictEqual(greeting, '¡Hola Amigo!');

  const farewell = translate(i18n, 'Goodbye %s', 'Amigo');
  assert.strictEqual(farewell, '¡Adiós Amigo!');
}

console.log('PASS: pkg:npm/y18n@5.0.8 contract verified');