Lingui.jsローカリゼーション: POファイル、React i18n & 自動化

npm install @lingui/core @lingui/react
npm install --save-dev @lingui/cli @lingui/vite-plugin @lingui/babel-plugin-lingui-macro

// lingui.config.js
import { defineConfig } from "@lingui/cli";
import { formatter } from "@lingui/format-po";

export default defineConfig({
  sourceLocale: "en",
  locales: ["en", "fr", "de", "ja", "es", "zh-CN"],
  catalogs: [
    {
      path: "<rootDir>/src/locales/{locale}/messages",
      include: ["src"],
    },
  ],
  format: formatter({ lineNumbers: false }),
});

// vite.config.ts
import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import { lingui } from "@lingui/vite-plugin";

export default defineConfig({
  plugins: [
    react({
      babel: {
        plugins: ["@lingui/babel-plugin-lingui-macro"],
      },
    }),
    lingui(),
  ],
});

#: src/components/WelcomeBanner.js:6
msgid "Welcome to our platform"
msgstr ""

#: src/components/WelcomeBanner.js:8
msgid "Hello {userName}, check out your <0>dashboard</0> to get started."
msgstr ""

#: src/components/CartSummary.js:5
msgid "{itemCount, plural, =0 {Your cart is empty} one {You have # item in your cart} other {You have # items in your cart}}"
msgstr ""

#: src/components/WelcomeBanner.js:6
msgid "Welcome to our platform"
msgstr "Bienvenue sur notre plateforme"

#: src/components/WelcomeBanner.js:8
msgid "Hello {userName}, check out your <0>dashboard</0> to get started."
msgstr "Bonjour {userName}, consultez votre <0>tableau de bord</0> pour commencer."

#: src/components/CartSummary.js:5
msgid "{itemCount, plural, =0 {Your cart is empty} one {You have # item in your cart} other {You have # items in your cart}}"
msgstr "{itemCount, plural, =0 {Votre panier est vide} one {Vous avez # article dans votre panier} other {Vous avez # articles dans votre panier}}"

src/
├── locales/
│   ├── en/
│   │   └── messages.po       ← Source (English)
│   ├── fr/
│   │   └── messages.po       ← French
│   ├── de/
│   │   └── messages.po       ← German
│   ├── ja/
│   │   └── messages.po       ← Japanese
│   ├── es/
│   │   └── messages.po       ← Spanish
│   └── zh-CN/
│       └── messages.po       ← Chinese Simplified
├── components/
├── i18n.ts
├── App.tsx
└── ...

import { Trans } from "@lingui/react/macro";

function WelcomeBanner({ userName }) {
  return (
    <div>
      <h1>
        <Trans>Welcome to our platform</Trans>
      </h1>
      <p>
        <Trans>
          Hello {userName}, check out your <a href="/dashboard">dashboard</a> to
          get started.
        </Trans>
      </p>
    </div>
  );
}

import { useLingui } from "@lingui/react/macro";

function NotificationButton() {
  const { t } = useLingui();

  const showAlert = () => {
    alert(t`Your changes have been saved.`);
  };

  return (
    <button onClick={showAlert} aria-label={t`Save changes`}>
      <Trans>Save</Trans>
    </button>
  );
}

import { Trans } from "@lingui/react/macro";

// Auto-generated ID (from message content)
<Trans>Welcome to our platform</Trans>

// Explicit ID (developer-defined key)
<Trans id="nav.welcome">Welcome to our platform</Trans>

import { Trans } from "@lingui/react/macro";

<Trans comment="Shown on the homepage hero section above the fold">
  Start building with confidence
</Trans>

import { Plural } from "@lingui/react/macro";

function CartSummary({ itemCount }) {
  return (
    <p>
      <Plural
        value={itemCount}
        _0="Your cart is empty"
        one="You have # item in your cart"
        other="You have # items in your cart"
      />
    </p>
  );
}

// src/i18n.ts
import { i18n } from "@lingui/core";

export async function loadCatalog(locale: string) {
  const { messages } = await import(`./locales/${locale}/messages.po`);
  i18n.load(locale, messages);
  i18n.activate(locale);
}

// Initialize with default locale
loadCatalog("en");

export default i18n;

// src/App.tsx
import { I18nProvider } from "@lingui/react";
import { i18n } from "./i18n";

function App() {
  return (
    <I18nProvider i18n={i18n}>
      <YourAppContent />
    </I18nProvider>
  );
}

import { useState } from "react";
import { loadCatalog } from "./i18n";
import { Trans } from "@lingui/react/macro";

const LANGUAGES = {
  en: "English",
  fr: "Français",
  de: "Deutsch",
  ja: "日本語",
  es: "Español",
};

function LanguageSwitcher() {
  const [currentLocale, setCurrentLocale] = useState("en");

  const handleChange = async (locale: string) => {
    await loadCatalog(locale);
    setCurrentLocale(locale);
  };

  return (
    <select
      value={currentLocale}
      onChange={(e) => handleChange(e.target.value)}
    >
      {Object.entries(LANGUAGES).map(([code, name]) => (
        <option key={code} value={code}>
          {name}
        </option>
      ))}
    </select>
  );
}

# Extract messages from source code into PO catalogs
npx lingui extract

# Translate your PO files (manually, with a TMS, or with AI)

# Compile PO catalogs into optimized JS modules for production
npx lingui compile

# Install the CLI
npm install ai-l10n

# Translate your source PO file to multiple languages
npx ai-l10n translate src/locales/en/messages.po \
  --languages fr,de,ja,zh-CN,es,ko

{
  "scripts": {
    "extract": "lingui extract",
    "compile": "lingui compile",
    "translate": "ai-l10n translate src/locales/en/messages.po --languages fr,de,ja,zh-CN,es,ko --update",
    "i18n": "npm run extract && npm run translate && npm run compile",
    "prebuild": "npm run i18n",
    "build": "vite build",
    "dev": "vite"
  }
}

LANGUAGES = fr,de,ja,zh-CN,es,ko

extract:
	npx lingui extract

translate:
	npx ai-l10n translate src/locales/en/messages.po --languages $(LANGUAGES) --update

compile:
	npx lingui compile

i18n: extract translate compile

dev: i18n
	npx vite

build: i18n
	npx vite build