objectstack-i18n

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, 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. Runtime authoring — TranslationItem: a translation metadata item authored in the Studio / metadata API carries the same objects.* groups plus the locale it translates. There is only one shape; see "Authoring at Runtime" 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',
  },
  // translations: [MyTranslations],  ← register your bundles here (see below)
});

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. 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}}!',
  },
};

// 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:

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

Validation messages are not a translation group. validationMessages was removed in spec 17.0.0 — nothing ever read it, so a translated rule message was stored and never shown. Author the message on the rule itself (object.validations[].message), which the engine returns on every rejected write.

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

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

Option sub-keys are the option's stored value, never its display label: for options: [{ value: 'direct_mail', label: 'Direct Mail' }] write options: { direct_mail: '直邮' } — both 'Direct Mail' and 'direct-mail' parse, ship, and resolve to nothing.

os validate / os lint / os compile check this direction and report it as warnings (translation-target-unknown, translation-option-key-unknown): a key naming an object, field, view, action, param, section, app, nav item, dashboard or widget that does not exist is listed alongside the names that do. A bundle keyed to something since renamed still parses — the label just renders silently in its source locale while every neighbouring label resolves.

Authoring at Runtime: the translation Item

Translations do not have to ship as files. A translation metadata item — created in the Studio, through the metadata API, or by an agent — is one locale's worth of the same objects.* groups documented above, plus the locale it translates. There is exactly one shape; nothing converts between formats.

import { defineTranslation } from '@objectstack/spec/system';

export default defineTranslation({
  locale: 'zh-CN',
  objects: {
    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' } },
        status: { options: { active: '活跃', inactive: '停用' } },
      },
      _views: { all_accounts: { label: '全部客户' } },
      _sections: { basic_info: { label: '基本信息' } },
      _actions: {
        merge: { label: '合并客户', confirmText: '此操作无法撤销，确认合并？' },
      },
    },
  },
  apps: { crm: { label: '客户关系管理', navigation: { home: { label: '首页' } } } },
  messages: { 'common.save': '保存' },
});

Rules that differ from a file bundle:

• locale is required. A file bundle names its locales as map keys; an item carries its own. An item whose locale cannot be resolved is skipped by the runtime sync — a silent skip, which is why the field is mandatory rather than inferred from the item name.
• One locale per item. Author zh-CN and ja-JP as two items.
• Published items are loaded at boot and on every publish (no restart), and layer over the file bundles — an authored value wins over a shipped one for the same key; deleting the item restores the shipped value.

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

Retired: the o.* dialect

A second object-first shape keyed on o.{object_name} (with app, nav, dashboard, reports, notifications, errors, _globalOptions, _meta, namespace, and _actions.confirmMessage) was once documented for Studio-authored translations. No resolver ever read it, so items authored that way saved successfully and rendered nothing. It was removed — those keys are now rejected at save time with a message naming the group to use instead. Never author them, in files or at runtime.

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!"

No ICU MessageFormat

There is no ICU MessageFormat engine — interpolation is always simple {{variable}} substitution (the aspirational messageFormat config knob was removed). Author messages for simple substitution; ICU plural/select strings like {count, plural, one {1 message} other {# messages}} will not be evaluated. To pluralize, select the form in application code before calling t().

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.

os i18n extract --check — freshness, not coverage

If you commit generated bundles (*.generated.ts produced by os i18n extract), coverage is only half the gate:

os i18n extract <config> --locales=zh-CN,ja-JP --fill=default \
  --out=src/translations --check

--check writes nothing. It re-renders what a real extract would produce and fails if that differs from what is committed in --out, naming each stale or missing file and printing the regenerate command.

Use both gates — they answer different questions. os i18n check asks are the strings translated? (coverage: human work). extract --check asks are the generated bundles still what the schema produces? (freshness: machine output). Renaming a label, adding an object, or removing a spec key leaves coverage at 100% while the bundles quietly go stale — which is exactly how the platform's own bundles ended up carrying translations for keys the schema had already deleted, plus fields with no entry in any locale.

It runs in the same merge mode as a normal extract, so it never asks for re-translation: an up-to-date bundle re-extracts byte-identically. Requires --out — there is nothing to compare against without it.

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 — getCoverage, suggestTranslations — that no shipped implementation provides. Treat them as extension points for a custom workbench or TMS adapter. (getAppBundle / loadAppBundle were removed along with the o.* shape they returned.)

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:

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

Common Pitfalls

❌ The Retired o.* Shape

Everything reads objects.*. The o.* dialect was removed — it is not a "Studio format", not a secondary format, just gone. Files registered in that shape resolve to nothing; runtime items in that shape are rejected at save time.

// WRONG — in a file bundle AND in a `translation` item
{ o: { account: { label: '客户' } } }

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

Same rule for its sibling keys: app → apps, nav → apps.<app>.navigation.<id>.label, dashboard → dashboards, _globalOptions → objects.<obj>.fields.<field>.options, _meta.locale → top-level locale, and _actions.confirmMessage → _actions.confirmText.

❌ 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