João Salavisa
66 lines
2.5 KiB
TypeScript
66 lines
2.5 KiB
TypeScript
import { render } from "@testing-library/react";
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import i18next from "i18next";
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import { I18nextProvider, initReactI18next, useTranslation } from "react-i18next";
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import { describe, expect, it } from "vitest";
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/**
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* `initI18n()` is fire-and-forget: `ensureInitialized` calls `i18next.init()`
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* without awaiting it and immediately flips its `initialized` flag. That is only
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* safe because init with INLINE resources and NO backend completes
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* synchronously — if it did not, `I18nProvider` would mount before the instance
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* was ready, `useTranslation()` would suspend, and with no Suspense boundary
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* above the React root the tree would never commit: a blank page with no console
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* error, no page error and no unhandled rejection.
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*
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* This was raised in review on the grounds that i18next's `initAsync` defaults
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* to `true`. That option governs when a BACKEND's resource loading is scheduled;
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* with resources passed inline there is nothing to load. These tests pin the
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* behaviour we actually depend on, so a dependency bump or a future switch to
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* lazily-loaded catalogs fails here instead of shipping a blank app.
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*
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* A fresh instance is used deliberately: `vitest.setup.ts` pre-initializes the
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* shared one, so asserting against it would be vacuous.
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*/
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const RESOURCES = { en: { common: { hi: "Hello" } } };
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function freshInstance() {
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const instance = i18next.createInstance();
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void instance.use(initReactI18next).init({
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lng: "en",
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fallbackLng: "en",
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defaultNS: "common",
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ns: ["common"],
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resources: RESOURCES,
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interpolation: { escapeValue: false },
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returnNull: false,
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});
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return instance;
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}
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function Label() {
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const { t } = useTranslation();
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return <span data-testid="label">{t("common:hi")}</span>;
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}
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describe("i18next initializes synchronously with inline resources", () => {
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it("is initialized and translating before init() is awaited", () => {
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const instance = freshInstance();
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// Read immediately — no await, no tick.
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expect(instance.isInitialized).toBe(true);
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expect(instance.t("common:hi")).toBe("Hello");
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});
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it("does not suspend when rendered with no Suspense boundary", () => {
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const instance = freshInstance();
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// No <Suspense> anywhere in the tree, mirroring the real app root. If
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// useTranslation suspended, this render would throw instead of committing.
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const { getByTestId } = render(
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<I18nextProvider i18n={instance}>
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<Label />
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</I18nextProvider>,
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);
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expect(getByTestId("label").textContent).toBe("Hello");
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});
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});
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