feat: i18n check CI + add missings translations

.github/skills/complete-i18n-translations/SKILL.md

@@ -0,0 +1,44 @@
+---
+name: complete-i18n-translations
+description: "Use when adding, changing, or reviewing i18n strings, translation keys, or src/i18n/lang/*.json files. Ensure every supported language is complete before finishing."
+---
+
+# Complete i18n translations
+
+When changing user-facing text or translation keys, complete all supported
+translations in the same change. Do not leave missing keys, empty values, or
+English placeholders in other locales.
+
+## Supported languages
+
+The translation files are in `src/i18n/lang/`. The current supported languages
+are `de`, `en`, `es`, `fr`, `it`, `nl`, and `no`. Check the files in that
+directory, `src/i18n/index.js` and `src/i18n/datetime.js` if the supported
+locales may have changed; do not rely on a hard-coded list if the repository
+has moved on.
+
+## Procedure
+
+1. Add every new key, with an accurate, non-empty translation, to every
+   supported locale in `src/i18n/lang/<locale>.json`. When changing a string,
+   update all locale versions of that key. Preserve nested JSON structure,
+   placeholders (such as `{name}`), plural forms (`singular | plural`), and
+   existing terminology.
+2. When removing a key from the code, remove it from every locale.
+3. When adding a new language, add its `lang/<locale>.json` file and register
+   it in both `src/i18n/index.js` and `src/i18n/datetime.js`.
+4. If a translation is uncertain, do not silently copy English into another
+   locale as a placeholder. Ask for a translation decision or clearly flag
+   the unresolved language to the user.
+5. Run `npm run i18n:check` and resolve every reported issue. This check
+   validates key parity, non-empty string values, locale registration, and
+   JSON validity. It is required before reporting i18n work as complete.
+
+## Completion criteria
+
+- All translation files contain the changed keys in every supported language.
+- No translation value is empty or a placeholder copied from another locale
+  without an explicit decision.
+- Every supported locale is registered in `src/i18n/index.js` and
+  `src/i18n/datetime.js`.
+- `npm run i18n:check` passes.

.github/workflows/dev_opened_or_updated.yml

@@ -14,6 +14,21 @@ env:
 permissions: {}
 
 jobs:
+  i18n:
+    permissions:
+      contents: read
+    runs-on: [self-hosted, common]
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
+      - uses: actions/setup-node@v7
+        with:
+          node-version: "24"
+          check-latest: true
+      - name: Check missing translations
+        run: npm run i18n:check
+
   build-and-push:
     permissions:
       contents: read

README.md

@@ -122,7 +122,17 @@ When a new stable version of the Viewer is released, the `release` branch is aut
 
 ### Internationalization
 
-When adding code in `develop` branch it will trigger an update on POEditor.
+Translations live in `src/i18n/lang/<lang>.json`. The supported languages are the ones available in this directory,
+and each of them must be registered in `src/i18n/index.js` and `src/i18n/datetime.js`.
+
+The CI fails on pull requests if a translation is missing: every key must exist, with a non-empty value,
+in all supported languages.
+
+Run the check locally with:
+
+```bash
+npm run i18n:check
+```
 
 ## License
 

package.json

@@ -10,6 +10,7 @@
     "lint": "eslint --fix",
     "test:unit": "vitest run",
     "test:e2e": "cypress open",
+    "i18n:check": "node scripts/i18n-check.mjs",
     "release": "semantic-release"
   },
   "dependencies": {

scripts/i18n-check.mjs

@@ -0,0 +1,115 @@
+#! /usr/bin/env node
+
+/* eslint-disable */
+
+/**
+ * Check that every translation key exists, with a non-empty value, in every
+ * supported language.
+ *
+ * Supported languages are the ones available in `src/i18n/lang`.
+ * Exit with code 1 if anything is missing.
+ */
+
+import fs from "node:fs";
+import path, { dirname } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const ROOT_DIR = path.join(__dirname, "..");
+const LANG_DIR = path.join(ROOT_DIR, "src/i18n/lang");
+const I18N_INDEX_FILE = path.join(ROOT_DIR, "src/i18n/index.js");
+const DATETIME_FILE = path.join(ROOT_DIR, "src/i18n/datetime.js");
+const LANG_FILE_REGEXP = /^([a-z]{2})\.json$/;
+const IS_GITHUB_ACTIONS = process.env.GITHUB_ACTIONS === "true";
+
+const LANGUAGES = fs
+  .readdirSync(LANG_DIR)
+  .map(file => file.match(LANG_FILE_REGEXP)?.[1])
+  .filter(Boolean)
+  .sort();
+
+const errors = [];
+
+function report(file, message) {
+  errors.push({ file: path.relative(ROOT_DIR, file), message });
+}
+
+function flatten(obj, prefix = "", acc = new Map()) {
+  for (const [key, value] of Object.entries(obj)) {
+    const fullKey = prefix ? `${prefix}.${key}` : key;
+    if (value !== null && typeof value === "object" && !Array.isArray(value)) {
+      flatten(value, fullKey, acc);
+    } else {
+      acc.set(fullKey, value);
+    }
+  }
+  return acc;
+}
+
+/**
+ * Every key found in any language must exist with a non-empty string value
+ * in all languages.
+ */
+function checkLangFiles() {
+  const translations = {};
+  for (const lang of LANGUAGES) {
+    const file = path.join(LANG_DIR, `${lang}.json`);
+    try {
+      translations[lang] = flatten(JSON.parse(fs.readFileSync(file, "utf-8")));
+    } catch (error) {
+      report(file, `Invalid JSON: ${error.message}`);
+    }
+  }
+
+  const allKeys = new Set(
+    Object.values(translations).flatMap(keys => [...keys.keys()])
+  );
+
+  for (const [lang, keys] of Object.entries(translations)) {
+    const file = path.join(LANG_DIR, `${lang}.json`);
+    const missing = [...allKeys].filter(key => !keys.has(key)).sort();
+    const empty = [...keys]
+      .filter(([, value]) => typeof value !== "string" || value.trim() === "")
+      .map(([key]) => key)
+      .sort();
+    if (missing.length > 0) {
+      report(file, `${missing.length} missing key(s): ${missing.join(", ")}`);
+    }
+    if (empty.length > 0) {
+      report(file, `${empty.length} empty or non-string value(s): ${empty.join(", ")}`);
+    }
+  }
+}
+
+/**
+ * Check that every language is registered in the given source file.
+ */
+function checkRegistration(file, pattern) {
+  const source = fs.readFileSync(file, "utf-8");
+  const missing = LANGUAGES.filter(lang => !pattern(lang).test(source));
+  if (missing.length > 0) {
+    report(file, `Language(s) not registered: ${missing.join(", ")}`);
+  }
+}
+
+// ~~~{ Main }~~~
+
+checkLangFiles();
+checkRegistration(I18N_INDEX_FILE, lang => new RegExp(`import\\s+${lang}\\s+from\\s+["']\\./lang/${lang}\\.json["']`));
+checkRegistration(DATETIME_FILE, lang => new RegExp(`\\b${lang}\\s*:`));
+
+if (errors.length > 0) {
+  for (const { file, message } of errors) {
+    if (IS_GITHUB_ACTIONS) {
+      console.log(`::error file=${file}::${message}`);
+    } else {
+      console.error(`✖ ${file}: ${message}`);
+    }
+  }
+  console.error(`\ni18n check failed: ${errors.length} error(s) for languages [${LANGUAGES.join(", ")}].`);
+  process.exit(1);
+}
+
+console.log(`i18n check passed for languages [${LANGUAGES.join(", ")}].`);