objectstack-i18n

name	objectstack-i18n
description	Author ObjectStack translation bundles — object/field labels, view text, app navigation strings, automation messages — and configure locale fallback, coverage reporting, and the per-locale source layout. Use when the user is adding `*.translation.ts` files, wiring a new locale, or resolving missing-translation warnings. Do not use for general i18n library questions unrelated to ObjectStack bundles.
license	Apache-2.0
compatibility	Requires @objectstack/spec 16.x (Zod v4 schemas)
metadata	{"author":"objectstack-ai","version":"1.2","domain":"i18n","tags":"i18n, translation, locale, l10n, bundle, coverage"}

Internationalization — ObjectStack I18n Protocol

Expert instructions for designing internationalization (i18n) and localization (l10n) strategies using the ObjectStack specification. This skill covers translation bundle structures, locale configuration, object-first translation patterns, coverage detection, and integration with the I18nService.

---

When to Use This Skill

• You are configuring i18n for a new ObjectStack project.
• You need to create translation bundles for multiple locales.
• You are designing object-first translation structures (per-object translation files).
• You need to detect missing translations (os i18n check coverage analysis).
• You are extending the service contract with AI translation suggestions (TMS / machine-translation integrations).
• You are implementing locale-specific formatting (dates, numbers, currency). Related: workspace regional defaults (timezone, locale, currency) live in the tenant-scoped localization settings, are resolved onto each request's ExecutionContext, and are exposed at GET /api/v1/auth/me/localization; a currency field falls back to localization.currency when it omits its own (ADR-0053).
• You need to understand translation file organization strategies (bundled, per_locale, per_namespace).

---

Core Concepts

Translation Architecture Overview

1. Runtime format — objects.* (TranslationData): each locale is authored as one TranslationData value. All translatable content for an object (label, fields, options, views, sections, actions) is grouped under objects.{object_name}, with global groups (apps, messages, validationMessages, globalActions, dashboards, settings, metadataForms) at the top level.

2. Bundle registration: per-locale files are assembled with defineTranslationBundle({ en, 'zh-CN': … }) into a TranslationBundle (locale code → TranslationData) and registered via defineStack({ translations: [...] }). This is the format the runtime resolvers, os i18n extract, os i18n check, and the example apps all use.

3. Coverage detection: os i18n check compares registered bundles against source metadata to report missing keys per locale.

4. Secondary format — o.* (AppTranslationBundle): a separate object-first, single-locale format aimed at translation-workbench UIs, Studio-authored translation metadata, and the coverage-diff schemas. It is not what the stack translations array consumes — see "Secondary Format: AppTranslationBundle" below.

---

Translation Configuration

Stack-Level I18n Config

Configure i18n settings in your objectstack.config.ts:

import { defineStack } from '@objectstack/spec';

export default defineStack({
  i18n: {
    defaultLocale: 'en',
    supportedLocales: ['en', 'zh-CN', 'ja-JP', 'es-ES'],
    fallbackLocale: 'en',
    fileOrganization: 'per_locale',
    messageFormat: 'simple',
  },
  // translations: [MyTranslations],  ← register your bundles here (see below)
});

Property	Type	Required / Default	Description
defaultLocale	string	required	Default BCP-47 locale code
supportedLocales	string[]	required	All supported locales
fallbackLocale	string	optional	Fallback when translation missing
fileOrganization	'bundled' | 'per_locale' | 'per_namespace'	'per_locale'	Declared authoring convention — no runtime consumer (see below)
messageFormat	'simple' | 'icu'	'simple'	'icu' is EXPERIMENTAL — not enforced (see Message Interpolation)
lazyLoad	boolean	false	Declared only — no runtime consumer yet
cache	boolean	true	EXPERIMENTAL — not enforced; no runtime consumer reads it

BCP-47 Locale Codes: Use standard locale tags (e.g., en-US, zh-CN, pt-BR, en-GB).

---

File Organization Strategies

1. Bundled (Single File)

All locales in one file. Best for small projects with few objects.

src/translations/
  crm.translation.ts        # { en: {...}, "zh-CN": {...} }

When to use: Fewer than 5 objects, 2-3 locales, < 200 translation keys total.

2. Per-Locale (Recommended)

One file per locale containing all namespaces. Recommended when a single locale file stays under ~500 lines.

src/translations/
  en.ts                     # TranslationData for English
  zh-CN.ts                  # TranslationData for Chinese
  ja-JP.ts                  # TranslationData for Japanese

When to use: Medium projects (5-20 objects), 3-5 locales, organized by language.

3. Per-Namespace (Enterprise)

One file per namespace (object) per locale. Aligns with Salesforce DX and ServiceNow conventions.

i18n/
  en/
    account.json            # ObjectTranslationData
    contact.json
    common.json             # messages + app labels
  zh-CN/
    account.json
    contact.json
    common.json

When to use: Large projects (20+ objects), 5+ locales, team collaboration, CI/CD pipelines.

These are authoring conventions: your import graph assembles whichever layout you choose into the TranslationBundle values you register on the stack. The fileOrganization config field declares the convention but has no runtime consumer, and FileI18nAdapter's localesDir loads only flat top-level {locale}.json files (subdirectories are skipped) — a per-namespace tree must be assembled by your own imports or build step.

---

Authoring Translation Bundles (objects.*)

The canonical authoring path: one TranslationData per locale, assembled with defineTranslationBundle and registered on the stack. This mirrors the shipped example apps (src/translations/{en,zh-CN}.ts + index.ts):

// src/translations/en.ts — one TranslationData per locale
import { defineStack, defineTranslationBundle } from '@objectstack/spec';
import type { TranslationData } from '@objectstack/spec/system';

const en: TranslationData = {
  objects: {
    task: {
      label: 'Task',
      pluralLabel: 'Tasks',
      fields: {
        subject: { label: 'Subject', help: 'Brief title of the task' },
        status: {
          label: 'Status',
          options: {
            not_started: 'Not Started',
            in_progress: 'In Progress',
            completed: 'Completed',
          },
        },
        due_date: { label: 'Due Date' },
      },
      _views: {
        all_tasks: {
          label: 'All Tasks',
          emptyState: { title: 'No tasks yet', message: 'Create your first task' },
        },
      },
      _sections: {
        details: { label: 'Details' },
      },
      _actions: {
        complete: {
          label: 'Complete',
          confirmText: 'Mark this task as completed?',
          successMessage: 'Task completed',
        },
      },
    },
  },
  apps: {
    todo_app: { label: 'Todo Manager', description: 'Personal task management' },
  },
  messages: {
    'common.save': 'Save',
    'common.cancel': 'Cancel',
    'welcome.user': 'Welcome, {{userName}}!',
  },
  validationMessages: {
    completed_date_required: 'Completed date is required when status is Completed',
  },
};

// src/translations/zh-CN.ts — same shape, translated values
const zhCN: TranslationData = {
  objects: {
    task: {
      label: '任务',
      pluralLabel: '任务',
      fields: {
        subject: { label: '主题', help: '任务的简要标题' },
        status: {
          label: '状态',
          options: { not_started: '未开始', in_progress: '进行中', completed: '已完成' },
        },
        due_date: { label: '截止日期' },
      },
    },
  },
  apps: {
    todo_app: { label: '待办管理', description: '个人任务管理' },
  },
  messages: {
    'common.save': '保存',
    'common.cancel': '取消',
    'welcome.user': '欢迎，{{userName}}！',
  },
};

// src/translations/index.ts — assemble the locales into one bundle…
export const TodoTranslations = defineTranslationBundle({
  en,
  'zh-CN': zhCN,
});

// objectstack.config.ts — …and register it on the stack
export default defineStack({
  i18n: { defaultLocale: 'en', supportedLocales: ['en', 'zh-CN'] },
  translations: [TodoTranslations],
});

defineTranslationBundle validates the bundle at authoring time via .parse() — prefer it over a bare : TranslationBundle literal.

---

Object-Level Translation Structure

All translatable content for a single object is aggregated under objects.{object_name} with these sub-keys:

Sub-key	Holds
label / pluralLabel / description	Object-level text (label is required)
fields.{field_name}	label, help, placeholder, options (option value → label) per field
_views.{view_name}	label, description, emptyState.title / emptyState.message
_actions.{action_name}	label, confirmText, successMessage, params.{param_name}, resultDialog
_sections.{section_name}	Form section / tab label, description

Top-level groups alongside objects: apps (label, description, navigation), messages, validationMessages, globalActions (object-less actions), dashboards, settings, metadataForms, settingsCommon.

For the exact Zod shape (and any field that may have been added since), read node_modules/@objectstack/spec/src/system/translation.zod.ts — TranslationDataSchema, ObjectTranslationDataSchema, and FieldTranslationSchema.

---

Naming Conventions

Context	Convention	Example
Locale codes	BCP-47	en, en-US, zh-CN, pt-BR
Object keys in objects.*	snake_case	objects.project_task, objects.support_case
Field keys	snake_case	fields.first_name, fields.due_date
Option values	lowercase	options.status.in_progress
Message keys	dot-separated	common.save, validation.required

Critical: Object names and field keys in translation bundles must match the snake_case names defined in your Object and Field schemas.

---

Secondary Format: AppTranslationBundle (o.*)

AppTranslationBundle is a separate, object-first format for a single locale where per-object content lives under o.{object_name}. It targets translation workbench UIs, Studio-authored translation metadata, and the coverage/diff schemas. Do not use it in the files you register through defineStack({ translations: [...] }) — the runtime resolvers read objects.* (TranslationData).

Differences from the runtime format worth knowing:

• Objects live under o.* (not objects.*); extra groups are _meta, _globalOptions, app, nav, dashboard, reports, pages, notifications, errors.
• _options is keyed by field name → { optionValue: label } (not by picklist name).
• Actions use confirmMessage (the runtime format's _actions use confirmText / successMessage).
• namespace is a declared isolation field for multi-plugin bundles; no shipped code prefixes keys with it.
• _meta.direction: 'rtl' lets UI frameworks apply RTL CSS for locales like Arabic.

import type { AppTranslationBundle } from '@objectstack/spec/system';

const zh: AppTranslationBundle = {
  _meta: { locale: 'zh-CN', direction: 'ltr' },
  o: {
    account: {
      label: '客户',
      pluralLabel: '客户',
      fields: {
        name: { label: '客户名称', help: '公司或组织的法定名称' },
        industry: { label: '行业', options: { tech: '科技', finance: '金融' } },
      },
      _options: {
        status: { active: '活跃', inactive: '停用' }, // keyed by FIELD name
      },
      _views: { all_accounts: { label: '全部客户' } },
      _sections: { basic_info: { label: '基本信息' } },
      _actions: {
        merge: { label: '合并客户', confirmMessage: '此操作无法撤销，确认合并？' },
      },
    },
  },
  _globalOptions: { currency: { usd: '美元', eur: '欧元' } },
  app: { crm: { label: '客户关系管理', description: '管理销售流程' } },
  nav: { home: '首页', settings: '设置' },
  messages: { 'common.save': '保存' },
};

Exact Zod shape: node_modules/@objectstack/spec/src/system/translation.zod.ts — AppTranslationBundleSchema and ObjectTranslationNodeSchema.

---

Message Interpolation

Simple Format (Default)

Both shipped adapters (FileI18nAdapter and the in-memory fallback) substitute double-brace {{variable}} placeholders only — single braces pass through unchanged. (The schema docstring mentions {variable} notation, but that is not what the runtime implements.)

{
  "messages": {
    "welcome": "Welcome, {{userName}}!",
    "pagination": "Showing {{start}} to {{end}} of {{total}} items"
  }
}

Usage:

i18n.t('messages.welcome', 'en', { userName: 'Alice' });
// "Welcome, Alice!"

ICU MessageFormat [EXPERIMENTAL]

messageFormat: 'icu' is accepted by the config schema but not enforced. The schema's own liveness annotation reads: "[EXPERIMENTAL — 'icu' not enforced] No ICU MessageFormat engine is wired; messageFormat:'icu' is accepted but interpolation falls back to simple substitution." Until an engine ships, author messages for simple {{variable}} substitution — ICU plural/select strings like {count, plural, one {1 message} other {# messages}} will not be evaluated.

---

Translation Coverage

os i18n check

The working coverage path is the CLI:

os i18n check                          # every locale found in the config
os i18n check --locales=zh-CN          # scope to specific locales
os i18n check --strict --threshold=95  # CI gate: locale parity + minimum coverage

It compares registered bundles against source metadata and reports missing object/field/option/view/action keys per locale. Missing keys in the default locale are errors; --strict promotes non-default gaps to errors and --show-keys lists every missing key. os lint --i18n-strict folds the same gate into linting.

Diff & Coverage Schemas

The spec models coverage results for tooling: TranslationCoverageResult (totals, coveragePercent, per-group breakdown) and TranslationDiffItem — key (dot path), status (missing | redundant | stale), locale, optional sourceHash for stale detection, and AI-enrichment fields (aiSuggested, aiConfidence). Full Zod shape: node_modules/@objectstack/spec/src/system/translation.zod.ts — TranslationCoverageResultSchema, TranslationDiffItemSchema.

These schemas back the optional contract methods getCoverage() and suggestTranslations(), which no shipped adapter implements — point coverage workflows at os i18n check / os lint --i18n-strict instead.

---

AI-Powered Translation Suggestions

II18nService.suggestTranslations(locale, items) is an optional contract method that enriches diff items with aiSuggested / aiConfidence. It is contract-only today: no shipped adapter implements it, and there is no CLI command for it. Implement it on a custom adapter to integrate:

• Translation Management Systems (TMS) like Phrase, Crowdin, Lokalise
• Machine translation APIs (Google Translate, DeepL)
• Internal translation memory databases

Best Practice: Review and approve machine suggestions before committing them.

---

Integration with II18nService

Service Contract

II18nService is the kernel service (name 'i18n') that loads bundles and resolves keys with fallback:

import type { II18nService } from '@objectstack/spec/contracts';

(The contract's source .ts is not part of the published package — only src/**/*.zod.ts ships — so import the type from @objectstack/spec/contracts rather than reading node_modules source.)

Methods implemented by both shipped adapters (FileI18nAdapter from @objectstack/service-i18n, and the in-memory fallback @objectstack/core registers when no i18n plugin is present):

• t(key, locale, params?) — dot-path resolution (e.g. objects.account.label) with {{param}} interpolation and fallback-locale lookup
• getTranslations(locale) — full snapshot for a locale
• loadTranslations(locale, data) — programmatic load; deep-merges, so multiple plugins can each contribute their own objects.* slice
• getLocales() / getDefaultLocale() / setDefaultLocale()

The in-memory fallback additionally resolves locale codes (exact → case-insensitive → base language zh-CN → zh → variant zh → zh-CN).

The contract also declares optional methods — getAppBundle, loadAppBundle, getCoverage, suggestTranslations — that no shipped implementation provides. Treat them as extension points for a custom workbench or TMS adapter.

Plugin Setup

import { ObjectKernel } from '@objectstack/core';
import { I18nServicePlugin } from '@objectstack/service-i18n';

const kernel = new ObjectKernel();
kernel.use(new I18nServicePlugin({
  defaultLocale: 'en',
  localesDir: './i18n',
  fallbackLocale: 'en',
  registerRoutes: true,  // Auto-register REST endpoints
  basePath: '/api/v1/i18n',
}));

await kernel.bootstrap();

const i18n = kernel.getService<II18nService>('i18n');

localesDir loads only flat, top-level {locale}.json files from the directory (subdirectories are skipped). registerRoutes: true (the default) self-registers GET {basePath}/locales, /translations/:locale, and /labels/:object/:locale once an HTTP server is available.

---

Translation Workflow Best Practices

1. Extract Skeletons from Metadata

Scaffold ready-to-edit translation files from your stack config:

os i18n extract --locales=zh-CN --out=./src/translations

This writes <locale>.objects.generated.ts TypeScript modules (not JSON) — the default locale is filled from schema labels, other locales follow --fill (empty | default | todo). Other flags: --default-locale, --filter (regex over object/app names or key paths), --dry-run, --json.

2. Translate

Fill in the values manually. (AI suggestion is a contract-only concept — suggestTranslations() has no CLI and no shipped implementation.)

3. Verify Coverage

os i18n check --locales=zh-CN

Add --strict / --threshold=95 in CI to fail on locale gaps.

4. Commit & Register

Commit the translation files, import them into your bundle, and register it via defineStack({ translations: [...] }).

---

CRM I18n Blueprint

Reference implementation shape:

• Bundle entry: src/translations/index.ts (or crm.translation.ts)
• Locale files: src/translations/{en,zh-CN,ja-JP,es-ES}.ts

Use this structure for metadata apps:

Layer	CRM Pattern
Stack config	i18n.fileOrganization = 'per_locale' with explicit locale list
Translation assembly	One defineTranslationBundle call that imports per-locale files
Locale content	Object-scoped translations (objects.account.fields.*, _views, _actions) + global app/messages
Naming integrity	Translation object/field keys exactly match metadata machine names

For new locales, copy one locale file as a baseline, then run os i18n check before release.

---

Common Pitfalls

❌ Studio Shape in Runtime Bundles

The runtime resolvers read objects.* — the o.* shape belongs to the secondary AppTranslationBundle format only:

// Registered via defineStack({ translations }) — WRONG
{ o: { account: { label: '客户' } } }

// CORRECT (TranslationData)
{ objects: { account: { label: '客户' } } }

❌ Mismatched Object Names

Translation keys must match metadata exactly:

// Metadata
{ name: 'project_task' }

// Translation (WRONG)
{ objects: { projectTask: { label: '项目任务' } } }

// Translation (CORRECT)
{ objects: { project_task: { label: '项目任务' } } }

❌ Hardcoded Option Values

Always use lowercase machine values for options:

// Metadata
options: [
  { value: 'in_progress', label: 'In Progress' },
]

// Translation (WRONG)
options: { 'In Progress': '进行中' }

// Translation (CORRECT)
options: { in_progress: '进行中' }

❌ Ignoring Coverage Reports

Stale translations can cause confusion. Always run os i18n check before releases.

---

Quick-Start Template

One compact per-locale file — assemble locales with defineTranslationBundle and register via defineStack({ translations: [...] }) as shown in "Authoring Translation Bundles" above:

// src/translations/zh-CN.ts
import type { TranslationData } from '@objectstack/spec/system';

export const zhCN: TranslationData = {
  objects: {
    account: {
      label: '客户',
      pluralLabel: '客户',
      fields: {
        name: { label: '客户名称' },
        email: { label: '邮箱', placeholder: '输入邮箱地址' },
        status: {
          label: '状态',
          options: {
            active: '活跃',
            inactive: '停用',
          },
        },
      },
      _views: {
        all_accounts: { label: '全部客户' },
      },
    },
  },

  apps: {
    crm: { label: '客户关系管理' },
  },

  messages: {
    'common.save': '保存',
    'common.cancel': '取消',
  },
};

---

Verify your work

After editing a *.translation.ts bundle:

os i18n check   # translation coverage vs the default locale (missing-key report)
os validate     # the bundle conforms to the protocol schema (no artifact)
# or: os build  # the same schema gate, plus emits dist/

os i18n check lists keys missing per locale; os lint --i18n-strict turns coverage gaps into hard errors. In a scaffolded project the schema gate is npm run validate. See objectstack-platform → Verify your work.

---

References

See references/_index.md for the full list of Zod schemas (with one-line descriptions) — pointers into node_modules/@objectstack/spec/src/. Always Read the source for exact field shapes; do not rely on memory of property names.

See Also

• objectstack-data — For understanding object and field metadata structure
• objectstack-ui — For view, app, and action translations
• objectstack-automation — For workflow and flow message translations