build: reject duplicate generated translations

webui/tests/i18n-catalog-validation.test.mjs

@@ -0,0 +1,38 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { findDuplicateTranslationKeys } from "../scripts/i18n-catalog-validation.mjs";
+
+test("allows the same translation key once in each locale", () => {
+  const source = `
+    export const generatedTranslations = {
+      en: { "i18n:example.share.12345678": "Share" },
+      de: { "i18n:example.share.12345678": "Freigeben" }
+    };
+  `;
+
+  assert.deepEqual(findDuplicateTranslationKeys(source), []);
+});
+
+test("rejects duplicate keys within a generated locale catalog", () => {
+  const source = `
+    export const generatedTranslations = {
+      en: {
+        "i18n:example.share.12345678": "Share",
+        "i18n:example.share.12345678": "Share"
+      },
+      de: {
+        "i18n:example.share.12345678": "Freigabe",
+        "i18n:example.share.12345678": "Freigeben"
+      }
+    };
+  `;
+
+  const findings = findDuplicateTranslationKeys(source, "fixture.ts");
+
+  assert.equal(findings.length, 2);
+  assert.match(findings[0], /fixture\.ts:\d+:\d+ duplicate generated translation key/);
+  assert.match(findings[0], /locale "en"/);
+  assert.match(findings[1], /locale "de"/);
+  assert.ok(findings.every((finding) => finding.includes("first declared at line")));
+});